Coating agent consisting of at least three components, method for producing same and its utilization

ABSTRACT

A coating composition consisting of at least three components, comprising a component (I) comprising at least one oligomeric or polymeric resin containing functional groups which react with isocyanate groups, as binder (A), a component (II) comprising at least one polyisocyanate as crosslinking agent (F), and a component (III) which comprises water, wherein component (I), (II) and/or (III) comprise or comprises at least one constituent which is curable with actinic light and/or electron beams.

The present invention relates to a coating composition consisting of atleast three components (3K system) comprising a component (I) comprisingat least one oligomeric or polymeric resin containing functional groupswhich react with isocyanate groups, as binder (A), a component (II)comprising at least one poly-isocyanate as crosslinking agent (F), and acomponent (III) which comprises water. The present inventionadditionally relates to a process for preparing these coatingcompositions and also to the use of the coating compositions inautomotive OEM finishing, refinish, and for the coating of plastics, andalso as topcoat materials or primer-surfacers.

Coating compositions or 3K systems of the abovementioned type are knownfrom the German patents DE-A-195 42 626 and DE-A-44 21 823. These knowncoating compositions already have comparatively few surface problems,such as popping marks or structuring, and as regards gloss, relaxation,spraying reliability, fullness, weathering stability, and otherimportant technological properties they possess a good profile ofproperties.

The increasingly more stringent requirements of the market, however, aremaking it necessary to improve these known coating compositions stillfurther in terms of their homogeneity, stability, handling, and poppinglimits. Moreover, the solvent content is to be lowered further than hasbeen possible to date. Furthermore, even on forced drying, the known 3Ksystems should give coatings which have no surface defects. They shouldhave an even higher gasoline resistance and an even lower gray haze thanthe known 3K systems.

The invention accordingly provides the novel coating compositionconsisting of at least three components, comprising

(I) a component comprising at least one oligomeric or polymeric resincontaining functional groups which react with isocyanate groups, asbinder (A),

(II) a component comprising at least one polyisocyanate as crosslinkingagent (F), and

(III) a component which comprises water,

wherein component (I), (II) and/or (III) comprise or comprises at leastone constituent which is curable with actinic light and/or electronbeams.

In the text below the novel coating composition consisting of at leastthree components is referred to for the sake of brevity as the “coatingcomposition of the invention”.

The present invention further provides a process for preparing thecoating compositions of the invention, and also provides for their usein automotive OEM finishing, refinishing, and the coating of plastics,as topcoat materials or primer-surfacers.

In the light of the prior art it was unforeseeable that the solution ofthe problem, with all of its advantages, might be achieved by means ofthe constituents for use in accordance with the invention, curable withactinic light and/or electron beams.

In the text below, the constituents for use in accordance with theinvention and curable with actinic light and/or electron beams arereferred to for the sake of brevity as “constituents important to theinvention”.

The coating compositions of the invention are notable, surprisingly, fora profile of properties which is improved over the prior art in relationin particular to the gloss, fullness, low popping tendency, sprayingreliability, leveling, and insensitivity to forced drying, and also inrespect of the weathering stability of the resultant coatings of theinvention.

It is surprising, furthermore, that the coating compositions of theinvention comprising said at least three components may be preparedsimply by mixing without the need for complicated mixing and/ordispersing apparatus as described, for example, in the German patentDE-A-195 10 651. The coating compositions of the invention are thereforesuitable for the field of automotive OEM finishing and in particular ofautomotive refinish, since they can be prepared by the painter by simplemixing of the components prior to their application and can be cured atlow temperatures.

A further advantage is that the coating compositions of the inventionprepared from said at least three components contain only a smallfraction of volatile organic solvents, despite the fact that the coatingcompositions are prepared using crosslinkers and binders dispersedand/or dissolved in organic media.

Moreover, the coating compositions of the invention ensure a high levelof variability, since it is possible to use not only the crosslinkingagents, pigments and additives that are recommended for aqueous coatingcompositions but also those used in conventional systems.

Finally, a feature of the inventive components of the coatingcompositions of the invention is a very good storage stability, whichcorresponds to that of conventional coating compositions.

The constituent of the coating compositions of the invention that isimportant to the invention is curable with actinic light, especially UVradiation, and/or electron beams. In the coating composition of theinvention it is present in an amount, based on the overall amount of thecoating composition of the invention, of from 0.1 to 80% by weight,preferably from 1 to 60% by weight, with particular preference from 1 to40% by weight. In special cases the coating composition of the inventionmay contain more than 80% by weight of the constituent that is importantto the invention.

The constituent that is important to the invention is present incomponent (I), (II) and/or (III). Where it is present in more than onecomponent, such as in components (I), (II) and (III), in components (I)and (II), in components (I) and (III) or in components (II) and (III),the respective amounts are chosen so that they are not above or belowthe abovementioned limits for the overall amount of the constituent thatis essential the invention.

Where the constituent that is essential to the invention is included, oris present solely, in component (II), it should not contain anyfunctional groups which react rapidly with the crosslinking agent (F),in order to prevent premature crosslinking of this component.

Where the constituent that is important to the invention is included in,or is present solely in, component (III), it is dispersible or solublein water.

In accordance with the invention it is of advantage if the constituentthat is important to the invention is present solely in one component(I), (II) or (III), and for this reason this variant is employed withpreference. Particular advantages result if the constituent that isimportant to the invention is present solely in the component (I),because in that case the corresponding coating compositions of theinvention have particular advantages, and are therefore used with veryparticular preference.

The constituent that is essential to the invention is a liquid or asolid and is soluble or dispersible in organic solvents and/or aqueousmedia, especially water. It may also be soluble or dispersible only inorganic solvents and not in aqueous media. Conversely, it may be solubleor dispersible in aqueous media but not in organic solvents. Theselection by the skilled worker of a particular constituent that isimportant to the invention, for the preparation of the coatingcomposition of the invention, is guided in particular by theconsideration of whether the constituent is to be included, or usedalone, in component (III). The skilled worker will therefore be able toselect easily, for each individual case, the most advantageousconstituent that is important to the invention.

Suitable constituents that are important to the invention include inprinciple all low molecular mass, oligomeric and polymeric compoundsthat are curable with actinic light and/or electron beams, suchcompounds being as commonly used in the field of UV curable or electronbeam curable coating compositions.

These radiation curable coating compositions normally include at leastone, preferably two or more, radiation curable binders, based inparticular on ethylenically unsaturated prepolymers and/or ethylenicallyunsaturated oligomers, one or more reactive diluents, where appropriate,and one or more photoinitiators, where appropriate.

In accordance with the invention it is of advantage if the constituentthat is important to the invention comprises at least one radiationcurable binder. In addition, the constituent that is important to theinvention may comprise one or more reactive diluents and/or one or morephotoinitiators. Photoinitiators are present therein especially when thebinders are curable with actinic light, especially UV radiation.

Examples of binders employed include (meth)acryloyl-functional(meth)acrylic copolymers, polyether acrylates, amine-modified polyetheracrylates, polyester acrylates, unsaturated polyesters, epoxy acrylates,urethane acrylates, amino acrylates, melamine acrylates, siliconeacrylates, and the corresponding methacrylates. It is preferred to usebinders that are free from aromatic structural units. Preference istherefore given to using urethane (meth)acrylates and/or polyester(meth)acrylates, with particular preference aliphatic urethaneacrylates.

The oligomers or polymers used as binders normally have a number averagemolecular weight of from 500 to 50 000, preferably from 1 000 to 5 000.

In the coating compositions of the invention it is preferred to usepolymers and/or oligomers containing per molecule at least 2, withparticular preference from 3 to 6, double bonds. The binders usedpreferably also have a double bond equivalent weight of from 400 to 2000, with particular preference from 500 to 900. Additionally, thebinders preferably have a viscosity at 23° C. of from 250 to 11 000mPa.s.

Polyester (meth)acrylates are known in principle to the skilled worker.They may be prepared by a variety of methods. For example, acrylic acidand/or methacrylic acid may be used directly as acid components in thesynthesis of the polyesters. A further possibility is to usehydroxyalkyl esters of (meth)acrylic acid as an alcohol componentdirectly in the synthesis of the polyesters. Preferably, however, thepolyester (meth)acrylates are prepared by acrylating polyesters. Forexample, it is possible first to synthesize hydroxyl-containingpolyesters which are then reacted with acrylic or methacrylic acid. Itis also possible first to synthesize carboxyl-containing polyesterswhich are then reacted with a hydroxyalkyl ester of acrylic ormethacrylic acid. Unreacted (meth)acrylic acid may be removed from thereaction mixture by washing, distilling or, preferably, by reacting withan equivalent amount of a monoepoxide or diepoxide compound usingappropriate catalysts, such as triphenylphosphine, for example. Forfurther details regarding the preparation of the polyester acrylates,reference may be made in particular to DE-A 33 16 593 and DE-A 38 36 370and also to EP-A-54 105, DE-B 20 03 579, and EP-B 2866.

Polyether (meth)acrylates, including those which have been aminemodified, are likewise known in principle to the skilled worker. Theymay be prepared by a variety of methods. For example,hydroxyl-containing polyethers which are esterified with acrylic acidand/or methacrylic acid may be obtained by reacting dihydric and/orhigher polyhydric alcohols with different amounts of ethylene oxideand/or propylene oxide in accordance with well-known methods (cf., e.g.,Houben-Weyl, volume XIV, 2, Makromolekulare Stoffe II,(1963)). It isalso possible to use polymerization products of tetrahydrofuran orbutylene oxide.

Flexibilization of the polyether (meth)acrylates, including those whichhave been amine modified, and of the polyester (meth)acrylates ispossible, for example, by reacting corresponding OH-functionalprepolymers and/or oligomers (based on polyether or polyester) withrelatively long-chain, aliphatic dicarboxylic acids, especiallyaliphatic dicarboxylic acids having at least 6 carbon atoms, such asadipic acid, sebacic acid, dodecanedioic acid and/or dimer fatty acids,for example. This flexibilization reaction may be carried out before orafter the addition of acrylic and/or methacrylic acid onto the oligomersand/or prepolymers.

Furthermore, epoxy (meth)acrylates are also well known to the skilledworker and therefore need not be elucidated further here. They arecustomarily prepared by subjecting acrylic acid to addition reactionwith epoxy resins, for example, with epoxy resins based on bisphenol A,or other commercially customary epoxy resins.

Flexibilizing the epoxy (meth)acrylates is possible in a similar way,for example, by reacting corresponding epoxy-functional prepolymersand/or oligomers with relatively long-chain, aliphatic dicarboxylicacids, especially aliphatic dicarboxylic acids having at least 6 carbonatoms, such as adipic acid, sebacic acid, dodecanedioc acid and/or dimerfatty acids, for example. This flexibilization reaction may be carriedout before or after the addition of acrylic and/or methacrylic acid ontothe oligomers and/or prepolymers.

Urethane (meth)acrylates are likewise well known to the skilled workerand need therefore not be elucidated further. They may be obtained byreacting a diisocyanate or polyisocyanate with a chain extender from thegroup of the diols/polyols and/or diamines/polyamines and/ordithiols/polythiols and/or alkanolamines and then reacting some or allof the remaining free isocyanate groups with at least one hydroxyalkyl(meth)acrylate or hydroxyalkyl ester of other ethylenically unsaturatedcarboxylic acids.

Examples of suitable diisocyanates or polyisocyanates are

the crosslinking agents (F) described below,

the diisocyanates or polyisocyantes described below, as are suitable forpreparation of the polyurethane resins described below, and also

1,3-bis(isocyanatomethyl)cyclohexane, diisocyanates derived from dimerfatty acids, as sold under the commercial designation DDI 1410 byHenkel, 1,8-diisocyanto-4-isocyanatomethyloctane,1,7-diisocyanato-4-isocyanatomethylheptane, or1-isocyanato-2-(3-isocyanatopropyl)cyclohexane.

conversely, the aforementioned urethane (meth)acrylates which stillcontain free isocyanate groups may be used as crosslinking agents (F).

The amounts of chain extender, diisocyanate and/or polyisocyanate, andhydroxyalkyl ester are preferably chosen so that

1.) the equivalents ratio of the NCO groups to the reactive groups ofthe chain extender (hydroxyl, amino and/or mercaptyl groups) is situatedbetween 3:1 and 1:2, preferably at 2:1, and

2.) the OH groups of the hydroxyalkyl esters of the ethylenicallyunsaturated carboxylic acids are present in a stoichiometric amount inrelation to the remaining free isocyanate groups of the prepolymerformed from isocyanate and chain extender.

Another possibility is to prepare the polyurethane acrylates by firstreacting some of the isocyanate groups of a diisocyanate orpolyisocyanate with at least one hydroxyalkyl ester and then to reactthe remaining isocyanate groups with a chain extender. In this case aswell the amounts of chain extender, isocyanate and hydroxyalkyl esterare chosen so that the equivalents ratio of the NCO groups to thereactive groups of the chain extender is situated between 3:1 and 1:2,preferably at 2:1, and the equivalents ratio of the remaining NCO groupsto the OH groups of the hydroxyalkyl ester is 1:1. Of course, all formsintermediate between these two methods are also possible. For example, aportion of the isocyanate groups of a diisocyanate may be reacted firstwith a diol, then a further portion of the isocyanate groups may bereacted with the hydroxyalkyl ester, after which the remainingisocyanate groups may be reacted with a diamine.

These various preparation methods for the polyurethane acrylates areknown (cf., e.g., EP-A-204 161) and therefore require no furtherdescription.

Flexibilization of the urethane (meth)acrylates is possible, forexample, by reacting corresponding isocyanate-functional prepolymersand/or oligomers with relatively long-chain, aliphatic diols and/ordiamines, especially aliphatic diols and/or diamines having at least 6carbon atoms. This flexibilization reaction may be carried out before orafter the addition of acrylic and/or methacrylic acid onto the oligomersand/or prepolymers.

Further examples of suitable binders are the following, commerciallyavailable products:

urethane acrylate Crodamer® UVU300 from Croda Resins Ltd., Kent, GB;

aliphatic urethane triacrylate Genomer® 4302 from Rahn Chemie, CH;

aliphatic urethane diacrylate Ebecryl® 284 from UCB, Drogenbos, Belgium;

aliphatic urethane diacrylate Ebecryl® 294 from UCB, Drogenbos, Belgium;

aliphatic urethane triacrylate Roskydal® LS 2989 from Bayer AG;

aliphatic urethane diacrylate Roskydal® V94-504 from Bayer AG, Germany;

aliphatic hexafunctional urethane acrylate Viaktin® VTE 6160 fromVianova, Austria;

aliphatic urethane diacrylate Laromer® 8987 from BASF AG;

aliphatic urethane diacrylate Laromer® 8861 from BASF AG, andexperimental modifications thereof.

The reactive diluents are commonly ethylenically unsaturated compounds.The reactive diluents may be monounsaturated, diunsaturated orpolyunsaturated.

Examples of suitable reactive diluents are (meth)acrylic acid and estersthereof, maleic acid and its esters, including monoesters, vinylacetate, vinyl ethers or vinylureas, especially alkylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanedioldi(meth)acrylate, vinyl (meth)acrylate, allyl (meth)acrylate, glyceroltri(meth)acrylate, trimethylolpropane tri(meth)acrylate,trimetholylpropane di(meth) acrylate, styrene, vinyltoluene,divinylbenzene, pentaerythritol tri(meth) acrylate, pentaerythritoltetra(meth)acrylate, dipropylene glycol di(meth)acrylate, hexanedioldi(meth)acrylate, ethoxyethoxyethyl acrylate, N-vinylpyrrolidone,phenoxyethyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl (meth)acrylate, butoxyethyl acrylate, isobornyl (meth)acrylate,tert-butylcyclohexyl acrylate, dimethylacrylamide, dicyclopentylacrylate, 1,12-dodecyl diacrylate, the reaction product of 2 mol ofacrylic acid with one mole of a dimer fatty alcohol having generally 36carbon atoms, or the long-chain linear diacrylates described in EP-A-250631 and having a molecular weight of from 400 to 4 000, preferably from600 to 2 500. For example, the two acrylate groups may be separated by apolyoxybutylene structure.

Advantageous reactive diluents are monoacrylates and/or diacrylates,such as isobornyl acrylate, tert-butylcyclohexyl acrylate, hexanedioldiacrylate, tripropylene glycol diacrylate, Laromer® 8887 from BASF AG,and Actilane® 423 from Akros Chemicals Ltd., GB. Particular preferenceis given to using isobornyl acrylate, hexanediol diacrylate, andtripropylene glycol diacrylate.

Particularly suitable photoinitiators are benzophenones, benzoins orbenzoin ethers, preferably benzophenone in UV formulations. It is alsopossible to use, for example, the products available commercially underthe names Irgacure® 184, Irgacure® 1800 and Irgacure® 500 from CibaGeigy, Genocure® MBF from Rahn, and Lucirin® TPO from BASF AG.

The further important constituent of component (I) of the coatingcomposition of the invention is at least one oligomeric or polymericresin containing functional groups which react with isocyanate groups,as binder (A).

Examples of suitable functional groups for use in accordance with theinvention that react with isocyanate groups are amino, thio and/orhydroxyl groups, of which the hydroxyl groups are particularlyadvantageous and are therefore particularly preferred in accordance withthe invention.

Accordingly, the binders (A) which are preferred in accordance with theinvention comprise hydroxyl-containing oligomeric or polymeric resins.

Examples of suitable binders (A) preferred in accordance with theinvention are hydroxyl-containing linear and/or branched and/or block,comb and/or random poly(meth)acrylates, polyesters, alkyds,polyurethanes, acrylated polyurethanes, acrylated polyesters,polylactones, polycarbonates, polyethers, epoxy resin-amine adducts,(meth)acrylatediols, partially saponified polyvinyl esters or polyureas,of which the poly (meth)acrylate, the polyesters, the polyurethanes, thepolyethers, and the epoxy resin-amine adducts are particularlyadvantageous and are therefore used with particular preference.

Regarding the preparability, the handling and the particularlyadvantageous properties of the coating compositions of the inventionthat are prepared using them, the poly (meth)acrylates, the polyestersand/or the polyurethanes afford very particular advantages, and so areused with very particular preference in accordance with the invention.

Besides the hydroxyl groups, these binders (A) may contain otherfunctional groups as well, such as acryloyl, amide, imide, carbonate orepoxide groups.

In accordance with the invention it is further of advantage if at leastone of the binders employed in each case in component (I), or all of thebinders (A) employed in each case in component (I), are individuallydispersible or soluble in water.

Examples of suitable water-soluble or water-dispersible binders containalternatively

(i) functional groups which can be converted into cations byneutralizing agents and/or quaternizing agents, and/or cationic groups,or

(ii) functional groups which can be converted into anions byneutralizing agents, and/or anionic groups, and/or

(iii) nonionic hydrophilic groups.

Examples of suitable functional groups for use in accordance with theinvention that be converted into cations by neutralizing agents and/orguaternizing agents are primary, secondary or tertiary amino groups,secondary sulfide groups or tertiary phosphine groups, especiallytertiary amino groups or secondary sulfide groups.

Examples of suitable cationic groups for use in accordance with theinvention are primary, secondary, tertiary or quaternary ammoniumgroups, tertiary sulfonium groups or quaternary phosphonium groups,preferably quaternary ammonium groups or tertiary sulfonium groups, butespecially tertiary sulfonium groups.

Examples of suitable functional groups for use in accordance with theinvention that may be converted into anions by neutralizing agents arecarboxylic acid, sulfonic acid or phosphonic acid groups, especiallycarboxylic acid groups.

Examples of suitable anionic groups for use in accordance with theinvention are carboxylate, sulfonate or phosphonate groups, especiallycarboxylate groups.

Examples of suitable nonionic hydrophilic groups for use in accordancewith the invention are polyether groups, especially poly(alkylene ether)groups.

Regarding the preparability, handling and particularly advantageousproperties of the coating compositions of the invention prepared usingthem, the binders (A) which contain the anion-forming groups and/oranions (ii), especially the carboxylic acid and/or the carboxylategroups, afford very particular advantages, and so are used with veryparticular preference in accordance with the invention.

Examples of very particularly preferred binders (A) of thelast-mentioned type, for use in accordance with the invention, are

(A1) acrylate copolymers (A1) which are dispersible or soluble in one ormore organic, optionally water dilutable solvents, contain hydroxylgroups and carboxylic acid and/or carboxylate groups, and have a numberaverage molecular weight Mn of between 1 000 and 30 000 daltons, an OHnumber of from 40 to 200 mg KOH/g, and an acid number of from 5 to 150mg KOH/g,

(A2) polyester resins (A2) which are dispersible or soluble in one ormore organic, optionally water dilutable solvents, contain hydroxylgroups and carboxylic acid and/or carboxylate groups, and have a numberaverage molecular weight Mn of between 1 000 and 30 000 daltons, an OHnumber of from 30 to 250 mg KOH/g, and an acid number of from 5 to 150mg KOH/g, and/or

(A3) polyurethane resins (A3) which are dispersible or soluble in one ormore organic, optionally water dilutable solvents, contain hydroxylgroups and carboxylic acid and/or carboxylate groups, and have a numberaverage molecular weight Mn of between 1 000 and 30 000 daltons, an OHnumber of from 20 to 200 mg KOH/g, and an acid number of from 5 to 150mg KOH/g.

The binders (A1), (A2) and (A3) are present individually or as a mixturein component (I), and may further comprise at least one of theabove-described binders (A), with the exception of those binders (A)which contain functional groups (i) that can be converted into cationsby neutralizing agents and/or quaternizing agents, and/or cationicgroups (i). In the text below, these binders (A) which may be used ifdesired with the binders (A1), (A2) and/or (A3) are referred to asbinders (A4).

In accordance with the invention, the components (I) which contain thebinders (A1), (A2) and/or (A3) and also, if desired, (A4) afford veryparticular advantages and are therefore used with very particularpreference.

Similarly, the coating compositions of the invention which comprise thisvery particularly preferred component (I) afford very particularadvantages and are therefore used with very particular preference.

If the mixing of the components (I), (II) and (III) is to take place bymanual stirring, it is of advantage for the coating composition of theinvention if the binders (A), especially the binders (A1), (A2), and/or(A3) and (A4), are selected such that their 50% strength solution of thebinder (A) in ethoxyethyl propionate at 23° C. has a viscosity of ≦10dpas. Where mechanical mixing is to take place, it is possible to usebinders (A) of higher viscosity, whose 50% strength solution inethoxyethyl propionate at 23° C. has a viscosity of ≦100 dpas. Theviscosity is limited at the top end only by the performance capacity ofthe mixing equipment.

Suitable acrylate copolymers (A1) include all acrylate copolymers havingthe stated OH numbers, acid numbers, molecular weights, and viscosities.

In particular, use is made of acrylate copolymers (A1) obtainable bypolymerizing in an organic solvent or solvent mixture and in thepresence of at least one polymerization initiator,

a1) a (meth)acrylic ester which is substantially free from acid groupsand is different from but copolymerizable with (a2), (a3), (a4), (a5),and (a6), or a mixture of such monomers,

a2) an ethylenically unsaturated monomer which carries at least onehydroxyl group per molecule and is substantially free from acid groups,and which is copolymerizable with (a1), (a3), (a4), (a5), and (a6) butdifferent from (a5), or a mixture of such monomers,

a3) an ethylenically unsaturated monomer which carries per molecule atleast one acid group which can be converted into the corresponding acidanion group, and which is copolymerizable with (a1), (a2), (a4), (a5),and (a6); or a mixture of such monomers, and

a4) if desired, one or more vinyl esters of alpha-branchedmonocarboxylic acids having from 5 to 18 carbon atoms per molecule,and/or

a5) if desired, at least one reaction product of acrylic acid and/ormethacrylic acid with the glycidyl ester of an alpha-branchedmonocarboxylic acid having from 5 to 18 carbon atoms per molecule, orinstead of the reaction product an equivalent amount of acrylic and/ormethacrylic acid which is then reacted during or after thepolymerization reaction with the glycidyl ester of an alpha-branchedmonocarboxylic acid having from 5 to 18 carbon atoms per molecule,

a6) if desired, an ethylenically unsaturated monomer which issubstantially free from acid groups, is copolymerizable with (a1), (a2),(a3), (a4), and

(a5) but different from (a1), (a2), (a4), and

(a5); or a mixture of such monomers,

in an organic solvent or solvent mixture and in the presence of at leastone polymerization initiator, the nature and amount of (a1), (a2), (a3),(a4), (a5), and (a6) being selected so that the polyacrylate resin (A1)has the desired OH number, acid number, and molecular weight.

To prepare the polyacrylate resins used in accordance with the inventionit is possible as component (a1) to use any (meth)acrylic alkyl orcycloalkyl ester which is copolymerizable with (a2), (a3), (a4), (a5),and (a6) and which has up to 20 carbon atoms in the alkyl radical,especially methyl, ethyl, propyl, n-butyl, sec-butyl, tert-butyl, hexyl,ethylhexyl, stearyl and lauryl acrylate or methacrylate; cycloaliphatic(meth)acrylic esters, especially cyclohexyl, isobornyl,dicyclopentadienyl, octahydro-4,7-methano-1H-indene-methanol ortert-butylcyclohexyl (meth)acrylate; (meth)acrylic oxaalkyl esters oroxacycloalkyl esters such as ethyl triglycol (meth)acrylate andmethoxyoligoglycol (meth)acrylate having a molecular weight Mn ofpreferably 550; or other ethoxylated and/or propoxylated, hydroxyl-free(meth)acrylic acid derivatives. These may contain minor amounts of(meth)acrylic alkyl or cycloalkyl esters of higher functionality, suchas ethylene glycol, propylene glycol, diethylene glycol, dipropyleneglycol, butylene glycol, 1,5-pentanediol, 1,6-hexanediol,octahydro-4,7-methano-1H-indenedimethanol or 1,2-, 1,3- or1,4-cyclohexanediol di(meth)acrylate; trimethylolpropane di- ortri(meth)acrylate; or pentaerythritol di-, tri- or tetra(meth)acrylate.In the context of the present invention, minor amounts of monomers ofrelatively high functionality are understood as being amounts which donot lead to crosslinking or gelling of the polyacrylate resins.

As component (a2) it is possible to use ethylenically unsaturatedmonomers which carry at least one hydroxyl group per molecule and aresubstantially free from acid groups, and are copolymerizable with (a1),(a3), (a4), (a5), and (a6) but different from (a5), such as hydroxyalkylesters of acrylic acid, methacrylic acid or another alpha,beta-ethylenically unsaturated carboxylic acid which are derived from analkylene glycol which is esterified with the acid or are obtainable byreacting the acid with an alkylene oxide, especially hydroxyalkyl estersof acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid,maleic acid, fumaric acid or itaconic acid in which the hydroxyalkylgroup contains up to 20 carbon atoms, such as 2-hydroxyethyl,2-hydroxypropyl, 3-hydroxypropyl, 3-hydroxybutyl, 4-hydroxybutylacrylate, methacrylate, ethacrylate, crotonate, maleate, fumarate oritaconate; 1,4-bis(hydroxymethyl)cyclohexane,octahydro-4,7-methano-1H-indenedimethanol, or methylpropanediolmonoacrylate, monomethacrylate, monoethacrylate, monocrotonate,monomaleate, monofumarate or monoitaconate; or reaction products ofthese hydroxyalkyl esters and cyclic esters, such asepsilon-caprolactone, for example; or olefinically unsaturated alcoholssuch as allyl alcohol or polyols such as trimethylolpropane monoallyl ordiallyl ether or pentaerythritol monoallyl, diallyl or triallyl ether.Regarding these monomers (a2) of higher functionality, the comments maderegarding the higher-functional monomers (a1) apply analogously. Thefraction of trimethylolpropane monoallyl ether is usually from 2 to 10%by weight, based on the overall weight of the monomers (a1) to (a6) usedto prepare the polyacrylate resin. In addition, however, it is alsopossible to add from 2 to 10% by weight, based on the overall weight ofthe monomers used to prepare the polyacrylate resin, oftrimethylolpropane monoallyl ether to the finished polyacrylate resin.The olefinic unsaturated polyols, such as trimethylolpropane monoallylether in particular, may be used as sole hydroxyl-containing monomers,but in particular may also be used proportionally in combination withother of the hydroxyl-containing monomers mentioned.

As component (a3), it is possible to use any ethylenically unsaturatedmonomer which carries at least one acid group, preferably a carboxylgroup, per molecule and is copolymerizable with (a1), (a2), (a4), (a5),and (a6); or a mixture of such monomers. Acrylic acid and/or methacrylicacid are used with particular preference as component (a3). It is,however, also possible to use other ethylenically unsaturated carboxylicacids having up to 6 carbon atoms in the molecule. Examples of suchacids are ethacrylic acid, crotonic acid, maleic acid, fumaric acid, anditaconic acid. A further possibility is to use ethylenically unsaturatedsulfonic or phosphonic acids, and/or their partial esters, as component(a3). Further suitable components (a3) includemono(meth)acryloyloxyethyl maleate, succinate, and phthalate.

As component (a4) use is made of one or more vinyl esters ofalpha-branched monocarboxylic acids having from 5 to 18 carbon atoms inthe molecule. The branched monocarboxylic acids may be obtained byreacting formic acid or carbon monoxide and water with olefins in thepresence of a liquid, strongly acidic catalyst; the olefins may becracking products of paraffinic hydrocarbons, such as mineral oilfractions, and may contain both branched and straight-chain acylicand/or cycloaliphatic olefins. The reaction of such olefins with formicacid or with carbon monoxide and water produces a mixture of carboxylicacids in which the carboxyl groups are located predominantly on aquaternary carbon atom. Other olefinic starting materials are, forexample, propylene trimer, propylene tetramer, and diisobutylene.Alternatively, the vinyl esters may be prepared conventionally from theacids, by reacting the acid with acetylene, for example. Particularpreference is given—owing to their ready availability—to using vinylesters of saturated aliphatic monocarboxylic acids having 9 to 11 carbonatoms that are branched on the alpha carbon atom.

As component (a5), the reaction product of acrylic acid and/ormethacrylic acid with the glycidyl ester of an alpha-branchedmonocarboxylic acid having from 5 to 18 carbon atoms per molecule isused. Glycidyl esters of highly branched monocarboxylic acids areavailable under the tradename Cardura. The reaction of the acrylic ormethacrylic acid with the glycidyl ester of a carboxylic acid having atertiary alpha carbon atom may take place before, during or after thepolymerization reaction. As component (a5) it is preferred to use thereaction product of acrylic and/or methacrylic acid with the glycidylester of Versatic acid. This glycidyl ester is available commerciallyunder the name Cardura E10.

As component (a6) it is possible to use all ethylenically unsaturatedmonomers that are substantially free from acid groups and arecopolymerizable with (a1), (a2), (a3), (a4), and (a5) but different from(a1), (a2), (a3), and (a4); or mixtures of such monomers. Suitablecomponents (a6) include

olefins, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene,cyclohexene, cyclopentene, norbornene, butadiene, isoprene,cyclopentadiene and/or dicyclopentadiene;

(meth)acrylamides such as (meth)acrylamide, N-methyl-, N,N-dimethyl-,N-ethyl-, N,N-diethyl-, N-propyl-, N,N-dipropyl, N-butyl-, N,N-dibutyl-,N-cyclohexyl- and/or N,N-cyclohexylmethyl-(meth)acrylamide;

monomers containing epoxide groups, such as the glycidyl ester ofacrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleicacid, fumaric acid and/or itaconic acid;

vinylaromatic hydrocarbons, such as styrene, alpha-alkylstyrenes,especially alpha-methylstyrene, and/or vinyltoluene;

nitriles such as acrylonitrile and/or methacryloynitrile;

vinyl compounds such as vinyl chloride, vinyl fluoride, vinylidenedichloride, vinylidene difluoride; N-vinylpyrrolidone; vinyl ethers suchas ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether,n-butyl vinyl ether, isobutyl vinyl ether and/or vinyl cyclohexyl ether;vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate,vinyl pivalate and/or the vinyl ester of 2-methyl-2-ethylheptanoic acid;and/or

polysiloxane macromonomers which have a number average molecular weightMn of from 1 000 to 40 000, preferably from 2 000 to 20 000, withparticular preference from 2 500 to 10 000, and in particular from 3 000to 7 000, and contain on average from 0.5 to 2.5, preferably from 0.5 to1.5, ethylenically unsaturated double bonds per molecule, as describedin DE-A 38 07 571 on pages 5 to 7, in DE-A 37 06 095 in columns 3 to 7,in EP-B-0 358 153 on pages 3 to 6, in U.S. Pat. No. 4,754,014 in columns5 to 9, in DE-A 44 21 823, or in the international patent application WO92/22615 on page 12, line 18 to page 18, line 10, oracryloxysilane-containing vinyl monomers, preparable by reactinghydroxy-functional silanes with epichlorohydrin and then reacting thatreaction product with methacrylic acid and/or hydroxyalkyl esters of(meth)acrylic acid.

It is preferred to use vinylaromatic hydrocarbons.

It is of advantage to use the polysiloxane macromonomers (a6) togetherwith other monomers (a6). In this case the amount of the polysiloxanemacromonomer or macromonomers (a6) for modifying the acrylate copolymers(A1) should be less than 5% by weight, preferably from 0.05 to 2.5% byweight, with particular preference from 0.05 to 0.8% by weight, based ineach case on the overall weight of the monomers used to prepare thecopolymer (A1). The use of such polysiloxane macromonomers leads to animprovement in the slip of the coatings of the invention.

The nature and amount of components (a1) to (a6) is selected such thatthe polyacrylate resin (A1) has the desired OH number, acid number, andglass transition temperature. Acrylate resins used with particularpreference are obtained by polymerizing

(a1) from 20 to 60% by weight, preferably from 30 to 50% by weight, ofcomponent (a1),

(a2) from 10 to 50% by weight, preferably from 15 to 40% by weight, ofcomponent (a2),

(a3) from 1 to 15% by weight, preferably from 1 to 8% by weight, ofcomponent (a3),

(a4) from 0 to 25% by weight, preferably from 5 to 15% by weight, ofcomponent (a4),

(a5) from 0 to 25% by weight, preferably from 5 to 15% by weight, ofcomponent (a5), and

(a6) from 5 to 30% by weight, preferably from 10 to 20% by weight, ofcomponent (a6),

the sum of the weight fractions of components (a1) to (a6) being in eachcase 100% by weight.

The polyacrylate resins (A1) used in accordance with the invention areprepared in an organic solvent or solvent mixture and in the presence ofat least one polymerization initiator. Organic solvents andpolymerization initiators used are the solvents and polymerizationinitiators which are customary for the preparation of polyacrylateresins and suitable for the preparation of aqueous dispersions. Thesolvents may participate in the reaction with the crosslinking component(II) and may therefore act as reactive diluents.

Examples of suitable reactive diluents are branched, cylic and/oracyclic C₉-C₁₆ alkanes functionalized with at least two hydroxyl groups.

Further examples of suitable reactive diluents are oligomeric polyolsobtainable by hydroformylation and subsequent hydrogenation ofoligomeric intermediates themselves obtained by metathesis reactions ofacyclic monoolefins and cyclic monoolefins; examples of suitable cyclicmonoolefins are cyclobutene, cyclopentene, cyclohexene, cyclooctene,cycloheptene, norbornene, and 7-oxanorbornene; examples of suitableacyclic monoolefins are contained in hydrocarbon mixtures obtained inpetroleum processing by cracking (C₅ cut); examples of suitableoligomeric polyols for use in accordance with the invention have ahydroxyl number (OHN) of from 200 to 450, a number average molecularweight Mn of from 400 to 1 000, and a mass average molecular weight Mwfrom 600 to 1 100;

Further examples of suitable reactive diluents are hyperbranchedcompounds having a tetrafunctional central group, derived fromditrimethylolpropane, diglycerol, ditrimethylolethane, pentaerythritol,tetrakis(2-hydroxyethyl)methane, tetrakis(3-hydroxy-propyl)methane or2,2-bishydroxymethyl-1,4-butanediol (homopentaerythritol). Thesereactive diluents may be prepared by the customary and known methods ofpreparing hyperbranched and dendrimeric compounds. Suitable synthesismethods are described, for example, in the patents WO 93/17060 and WO96/12754 or in the book by G. R. Newkome, C. N. Moorefield and F.Vögtle, “Dendritic Molecules, Concepts, Syntheses, Perspectives”, VCH,Weinheim, N.Y., 1996.

Further examples of suitable reactive diluents are polycarbonatediols,polyesterpolyols, poly(meth)-acrylatediols or hydroxyl-containingpolyaddition products.

Examples of suitable isocyanate-reactive solvents which may be regardedas monofunctional reactive diluents are butyl glycol, 2-methoxypropanol,n-butanol, methoxybutanol, n-propanol, ethylene glycol monomethyl ether,ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,diethylene glycol diethylene ether, diethylene glycol monobutyl ether,trimethylolpropane, ethyl 2-hydroxypropionate or3-methyl-3-methoxybutanol and also derivatives based on propyleneglycol, e.g., ethoxyethyl propionate, isopropoxypropanol ormethoxypropyl acetate.

Said reactive diluents, especially the functionalized alkanes, and/orthe isocyanate-reactive solvents may also be present in component (III).

It is also possible in this context first to prepare the polyacrylateresins (A1) in a solvent which is not water dilutable and following thepolymerization to replace some or all of this solvent by water dilutablesolvent.

Examples of suitable polymerization initiators are initiators which formfree radicals, such as tert-butyl peroxyethylhexanoate, benzoylperoxide, di-tert-amyl peroxide, azobisisobutyronitrile, and tert-butylperbenzoate, for example. The initiators are used preferably in anamount from 1 to 25% by weight, with particular preference from 2 to 10%by weight, based on the overall weight of the monomers.

The polymerization is appropriately conducted at a temperature from 80to 200° C., preferably from 110 to 180° C. Preferred solvents used areethoxyethyl propionate and isopropoxypropanol.

The polyacrylate resin (A1) is preferably prepared by a two-stageprocess, since in that way the resultant coating compositions of theinvention possess better processing properties. It is thereforepreferred to use polyacrylate resins which are obtainable by

1. polymerizing a mixture of (a1), (a2), (a4), (a5), and (a6), or amixture of portions of components (a1), (a2), (a4), (a5), and (a6), inan organic solvent and/or in one of the abovementioned reactivediluents,

2. after at least 60% by weight of the mixture consisting of (a1), (a2),(a4), (a5), and, where used (a6) have been added, adding (a3) and anyremainder of components (a1), (a2), (a4), (a5), and (a6), and continuingpolymerization, and

3. after the end of the polmerization, subjecting the resultingpolyacrylate resin if desired to at least partial neutralization, i.e.,converting the acid groups into the corresponding acid anion groups.

In addition, however, it is also possible to include components (a4)and/or (a5) in the initial charge together with at least part of thesolvent, and to meter in the remaining components. Moreover, it is alsopossible for components (a4) and/or (a5) to be included only in part inthe initial charge, together with at least part of the solvent, and forthe remainder of these components to be added as described above.Preferably, for example, at least 20% by weight of the solvent and about10% by weight of component (a4) and (a5), and also, if desired, portionsof components (a1) and (a6), are included in the initial charge.

Preference is also given to preparing the polyacrylate resins (A1) usedin accordance with the invention by means of a two-stage process whosefirst stage lasts from 1 to 8 hours, preferably from 1.5 to 4 hours, anda mixture of (a3) and any remainder of components (a1), (a2), (a4),(a5), and (a6) is added over the course of from 20 to 120 minutes,preferably over the course of from 30 to 90 minutes. Following the endof the addition of the mixture of (a3) and any remainder of components(a1), (a2), (a4), (a5), and (a6), polymerization is continued until allof the monomers used have undergone substantially complete reaction. Thesecond stage in this process may immediately follow the first.Alternatively, the second stage may be commenced after a certain time,for example after from 10 minutes to 10 hours.

The amount and rate of addition of the initiator are preferably chosenso as to give a polyacrylate resin (A1) having a number averagemolecular weight Mn of from 1 000 to 30 000 daltons. It is preferred tocommence the initiator feed at a certain time, generally about 15minutes, before the feeding of the monomers. Preference is given,further, to a process in which the addition of initiator is commenced atthe same point in time as the addition of the monomers and is endedabout half an hour after the addition of the monomers has ended. Theinitiator is preferably added in a constant amount per unit time.Following the end of the addition initiator, the reaction mixture isheld at polymerization temperature until (generally 1.5 hours) all ofthe monomers used have undergone substantially complete reaction.“Substantially complete reaction” is intended to denote that preferably100% by weight of the monomers used have undergone reaction but that itis also possible for a small residual monomer content of not more thanup to about 0.5% by weight, based on the weight of the reaction mixture,to remain unreacted.

Preferably, the monomers for preparing the polyacrylate resins (A1) arepolymerized at a polymerization solids which is not too high, preferablyat a polymerization solids of from 80 to 50% by weight, based on thecomonomers, and then the solvents are removed in part by distillation,so that the resulting polyacrylate resin solutions (A1) have a solidscontent of preferably from 100 to 60% by weight.

The preparation of the polyacrylate resins (A1) for use in accordancewith the invention has no special features in terms of its methodologybut instead takes place by means of the methods of continuous orbatchwise copolymerization that are known and customary in the polymersfield, under atmospheric pressure or superatmospheric pressure, instirred tanks, autoclaves, tube reactors or Taylor reactors.

Examples of suitable (co)polymerization processes are described in thepatents DE-A-197 09 465, DE-C-197 09 476, DE-A-28 48 906, DE-A-195 24182, EP-A-0 554 783, WO 95/27742 or WO 82/02387.

In accordance with the invention, Taylor reactors are advantageous andare therefore used with preference for the process of the invention.

Taylor reactors, which serve to convert substances under the conditionsof Taylor flow, are known. They consist substantially of two coaxialconcentric cylinders of which the outer is fixed and the inner rotates.The reaction space is the volume formed by the gap between thecylinders. Increasing angular velocity ω_(i) of the inner cylinder isaccompanied by a series of different flow patterns which arecharacterized by a dimensionless parameter, known as the Taylor numberTa. In addition to the angular velocity of the stirrer, the Taylornumber is also dependent on the kinematic viscosity ν of the fluid inthe gap and on the geometric parameters, the external radius of theinner cylinder r_(i), the internal radius of the outer cylinder r_(o),and the gap width d, the difference between the two radii, in accordancewith the following formula:

Ta=ω_(i) r _(i) dν⁻¹(d/r _(i))^(1/2)  (I)

where d=r_(o)−r_(i).

At low angular viscosity, the laminar Couette flow, a simple shear flow,develops. If the rotary speed of the inner cylinder is increasedfurther, then, above a critical level, alternately contrarotatingvortices (rotating in opposition) occur, with axes along the peripheraldirection. These vortices, called Taylor vortices, are rotationallysymmetric and have a diameter which is approximately the same size asthe gap width. Two adjacent vortices form a vortex pair or vortex cell.

The basis for this behavior is the fact that, in the course of rotationof the inner cylinder with the outer cylinder at rest, the fluidparticles that are near to the inner cylinder are subject to a greatercentrifugal force than those at a greater distance from the innercylinder. This difference in the acting centrifugal forces displaces thefluid particles from the inner to the outer cylinder. The centrifugalforce acts counter to the viscosity force, since for the motion of thefluid particles it is necessary to overcome the friction. Any increasein the rotary speed is accompanied by an increase in the centrifugalforce as well. The Taylor vortices are formed when the centrifugal forceexceeds the stabilizing viscosity force.

In the case of Taylor flow with a low axial flow, each vortex pairpasses through the gap, with only a low level of mass transfer betweenadjacent vortex pairs. Mixing within such vortex pairs is very high,whereas axial mixing beyond the pair boundaries is very low. A vortexpair may therefore be regarded as a stirred tank in which there isthorough mixing. Accordingly, the flow system behaves as an ideal flowtube in that the vortex pairs pass through the gap with constantresidence time, like ideal stirred tanks.

An advantage in accordance with the invention here are Taylor reactorshaving an external reactor wall located within which there is aconcentrically or eccentrically disposed rotor, a reactor floor, and areactor lid, which together define the annular reactor volume, at leastone means for metered addition of reactants, and a means for thedischarge of product, where the reactor wall and/or the rotor are or isgeometrically designed in such a way that the conditions for Taylor floware met over substantially the entire reactor length in the reactorvolume, i.e., in such a way that the annular gap broadens in thedirection of flow traversal.

Suitable polyesters (A2) include all polyesters having theabove-indicated OH numbers, acid numbers, molecular weights, andviscosities.

Use is made in particular of polyesters (A2) obtainable by reacting

p1) optionally sulfonated polycarboxylic acids or their esterifiablederivatives, together if desired with monocarboxylic acids,

p2) polyols, together if desired with monools,

p3) if desired, further modifying components, and

p4) if desired, a component which is reactive with the reaction productof (p1), (p2) and, where used, (p3).

Examples that may be given of polycarboxylic acids that may be used ascomponent (p1) are aromatic, aliphatic, and cycloaliphaticpolycarboxylic acids. As component (p1) it is preferred to use aromaticand/or aliphatic polycarboxylic acids.

Examples of suitable polycarboxylic acids are phthalic acid, isophthalicacid, terephthalic acid, phthalic, isophthalic or terephthalicmonosulfonate, halophthalic acids, such as tetrachlorophthalic ortetrabromophthalic acid, adipic acid, glutaric acid, azelaic acid,sebacic acid, fumaric acid, maleic acid, trimellitic acid, pyromelliticacid, tetrahydrophthalic acid, hexahydrophthalic acid,1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,1,4-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic acid,endomethylenetetrahydrophthalic acid, tricyclodecanedicarboxylic acid,endoethylenehexahydrophthalic acid, camphoric acid,cyclohexanetetracarboxylic acid, or cyclobutanetetracarboxylic acid. Thecycloaliphatic polycarboxylic acids may be used either in their cis orin their trans form or as a mixture of both forms. Also suitable are theesterifiable derivatives of the aforementioned polycarboxylic acids,such as their monoesters or polyesters with aliphatic alcohols havingfrom 1 to 4 carbon atoms or hydroxy alcohols having from 1 to 4 carbonatoms, for example. It is also possible to use the anhydrides of theabovementioned acids, where they exist.

If desired, together with the polycarboxylic acids it is also possibleto use monocarboxylic acids, such as benzoic acid, tert-butylbenzoicacid, lauric acid, isononanoic acid, and fatty acids of naturallyoccurring oils, for example. Isononanoic acid is a preferredmonocarboxylic acid used.

Suitable alcohol components (p2) for preparing the polyester (A2) arepolyhydric alcohols, such as ethylene glycol, propanediols, butanediols,hexanediols, neopentyl hydroxypivalate, neopentyl glycol, diethyleneglycol, cyclohexanediol, cyclohexanedimethanol, trimethylpentanediol,ethylbutylpropanediol, ditrimethylolpropane, trimethylolethane,trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol,trishydroxyethyl isocyanate, polyethylene glycol, polypropylene glycol,alone or together with monohydric alcohols, such as butanol, octanol,lauryl alcohol, cyclohexanol, tert-butylcyclohexanol, ethoxylated and/orpropoxylated phenols, for example.

Compounds suitable as component (p3) for preparing the polyesters (A2)include in particular those having a group which is reactive toward thefunctional groups of the polyester, with the exception of the compoundsspecified as component (p4). As modifying component (p3) it is preferredto use polyisocyanates and/or diepoxide compounds, and also, if desired,monoisocyanates and/or monoepoxide compounds. Suitable components (p3)are described, for example, in DE-A-40 24 204 on page 4, lines 4 to 9.

Compounds suitable as component (p4) for preparing the polyesters (A2)are those compounds which in addition to a group that is reactive towardthe functional groups of the polyester (A2) also contain a tertiaryamino group, examples including monoisocyanates containing at least onetertiary amino group, or mercapto compounds containing at least onetertiary amino group. For details, refer to DE-A-40 24 204, page 4,lines 10 to 49.

The polyesters (A2) are prepared in accordance with the known methods ofesterification, as is described, for example, in DE-A-40 24 204, page 4,lines 50 to 65. This reaction takes place usually at temperaturesbetween 180 and 280° C., in the absence or presence of an appropriateesterification catalyst, such as lithium octoate, dibutyltin oxide,dibutyltin dilaurate or para-toluenesulfonic acid, for example.

The polyesters (A2) are normally prepared in the presence of smallamounts of an appropriate solvent as entrainer. Examples of entrainersused include aromatic hydrocarbons, such as xylene in particular, and(cyclo)aliphatic hydrocarbons, e.g. cyclohexane or methylcyclohexane.

As component (A2) it is particularly preferred to use polyesters whichhave been prepared by a two-stage process, by first preparing ahydroxyl-containing polyester having an OH number of from 100 to 300 mgKOH/g, an acid number of less than 10 mg KOH/g, and a number averagemolecular weight Mn of from 500 to 2 000 daltons, which is then reactedin a second stage with carboxylic anhydrides to give the desiredpolyester (A2). The amount of carboxylic anhydrides in this case ischosen so that the resulting polyester has the desired acid number. Acidanhydrides suitable for this reaction are all those commonly used, suchas hexahydrophthalic anhydride, trimellitic anhydride, pyromelliticanhydride, phthalic anhydride, camphoric anhydride, tetrahydrophthalicanhydride, succinic anhydride, and mixtures of these and/or otheranhydrides, and especially anhydrides of aromatic polycarboxylic acids,such as trimellitic anhydride, for example.

It is possible if desired for the polyacrylate resin (A1to have beenprepared at least in part in the presence of polyesters (A2). In thiscase, advantageously at least 20% by weight and with particularadvantage from 40 to 80% by weight of the component (A1) are prepared inthe presence of the component (A2).

Any remainder of the component (A1) is added subsequently to the bindersolution. In this case it is possible for this already polymerized resinto have the same monomer composition as the polyacrylate resinsynthesized in the presence of the polyester. Alternatively, ahydroxyl-containing polyacrylate resin having a different monomercomposition may be added. Also possible is the addition of a mixture ofdifferent polyacrylate resins and/or polyesters, with possibly one resinhaving the same monomer composition as the polyacrylate resinsynthesized in the presence of the polyester.

As the polyurethane resin (A3) for use in accdordance with theinvention, containing hydroxyl and acid groups, suitable resins includeall polyurethane resins having the indicated OH numbers, acid numbers,molecular weights, and viscosities.

Suitable polyurethane resins (A3) are described, for example, in thefollowing documents: EP-A-355 433, DE-A-35 45 618, DE-A-38 13 866,DE-A-32 10 051, DE-A-26 24 442, DE-A-37 39 332, U.S. Pat. No. 4,719,132,EP-A-89 497, U.S. Pat. No. 4,558,090, U.S. Pat. No. 4,489,135, DE-A-3628 124, EP-A-158 099, DE-A-29 26 584, EP-A-195 931, DE-A-33 21 180 andDE-A-40 05 961.

In component (I) it is preferred to use polyurethane resins which arepreparable by reacting isocyanato-containing prepolymers with compoundsthat are reactive toward isocyanate groups.

The preparation of isocyanato-containing prepolymers may take place byreacting polyols having a hydroxyl number of from 10 to 1 800,preferably from 50 to 1 200 mg KOH/g, with excess polyisocyanates attemperatures of up to 150° C., preferably from 50 to 130° C., in organicsolvents which are unable to react with isocyanates. The equivalentsratio of NCO to OH groups is situated between 2.0:1.0 and >1.0:1.0,preferably between 1.4:1 and 1.1:1.

The polyols used to prepare the prepolymer may be of low molecularweight and/or high molecular weight and may contain groups that are slowto react and are anionic or capable of forming anions. It is alsopossible to use low molecular weight polyols having a molecular weightof from 60 up to 400 daltons to prepare the isocyanato-containingprepolymers. In this case amounts of up to 30% by weight of the overallpolyol constituents are used, preferably from about 2 to 20% by weight.

In order to obtain an NCO prepolymer of high flexibility, a highfraction of a predominantly linear polyol having a preferred OH numberof from 30 to 150 mg KOH/g should be added. Up to 97% by weight of theoverall polyol may consist of saturated and unsaturated polyestersand/or polyethers having a number average molecular weight Mn of from400 to 5 000 daltons. The selected polyetherdiols should not introduceexcessive amounts of ether groups, since otherwise the polymers formedstart to swell in water. Polyesterdiols are prepared by esterifyingorganic dicarboxylic acids or their anhydrides with organic diols, orderive from a hydroxycarboxylic acid or from a lactone. In order toprepare branched polyester polyols, it is possible to employ a minorproportion of polyols or polycarboxylic acids having a higherfunctionality.

The alcohol component used to prepare the polyurethane resins preferablyconsists at least to a certain extent of

u₁) at least one diol of the formula (I′)

in which R₁ and R₂ are each an identical or different radical and are analkyl radical having from 1 to 18 carbon atoms, an aryl radical or acycloaliphatic radical, with the proviso that R₁ and/or R₂ must not bemethyl, and/or

u₂) at least one diol of the formula (II′)

in which R₃, R₄, R₆ and R₇ are each identical or different radicals andare an alkyl radical having from 1 to 6 carbon atoms, a cycloalkylradical or an aryl radical and R₅ is an alkyl radical having from 1 to 6carbon atoms, an aryl radical or an unsaturated alkyl radical havingfrom 1 to 6 carbon atoms, and n is eiter 0 or 1.

Suitable diols (u₁) are all propanediols of the formula (I′) in whicheither R₁ or R₂ or R₁ and R₂ is or are other than methyl, such as2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-methyl-1,3-propanediol,2-phenyl-2-methyl-1,3-propanediol, 2-propyl-2-ethyl-1,3-propanediol,2-di-tert-butyl-1,3-propanediol, 2-butyl-2-propyl-1,3-propanediol,1-dihydroxymethyl-bicyclo[2.2.1]heptane, 2,2-diethyl-1,3-propanediol,2,2-dipropyl-1,3-propanediol, 2-cyclohexyl-2-methyl-1,3-propanediol, etcetera.

Examples of diols (u₂) (formula (II′)) that may be used include2,5-dimethyl-2,5-hexanediol, 2,5-diethyl-2,5-hexanediol,2-ethyl-5-methyl-2,5-hexanediol, 2,4-dimethyl-2,4-pentanediol,2,3-dimethyl-2,3-butanediol, 1,4-bis(2′-hydroxypropyl)benzene, and1,3-bis(2′-hydroxypropyl)benzene.

As diols (u₁) it is preferred to use 2-propyl-2-ethyl-1,3-propanediol,2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and2-phenyl-2-ethyl-1,3-propanediol, and as component (u₂) it is preferredto use 2,3-dimethyl-2,3-butanediol and also 2,5-dimethyl-2,5-hexanediol.Particular preference is given to using 2-butyl-2-ethyl-1,3-propanedioland also 2-phenyl-2-ethyl-1,3-propanediol as component (u₁) and2,5-dimethyl-2,5-hexanediol as component (u₂).

The diols (u₁) and/or (u₂) are commonly used in an amount of from 0.5 to15% by weight, preferably from 1 to 7% by weight, based in each case onthe overall weight of the synthesis components used to prepare thepolyurethanes (A3).

Typical multifunctional isocyanates used to prepare the polyurethaneresins are aliphatic, cycloaliphatic and/or aromatic polyisocyanatescontaining at least two isocyanate groups per molecule. Preference isgiven to the isomers or isomer mixtures of organic diisocyanates. Owingto their good stability to ultraviolet light, (cyclo)aliphaticdiisocyanates give rise to products having only a low tendency toyellow. The polyisocyanate component used to form the prepolymer mayalso contain a fraction of polyisocyanates of higher functionality,provided that no gelling is caused as a result. Products which havebecome established as triisocyanates are those formed by trimerizationor oligomerization of diisocyanates or by reaction of diisocyanates withpolyfunctional compounds containing OH or NH groups. The averagefunctionality may be lowered if desired by adding monoisocyanates.

Examples of polyisocyanates that may be used include phenylenediisocyanate, tolylene diisocyanate, xylylene diisocyanate, bisphenylenediisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate,isophorone diisocyanate, cyclobutane diisocyanate, cyclopentylenediisocyanate, cyclohexylene diisocyanate, methylcyclohexylenediisocyanate, dicyclohexylmethane diisocyanate, ethylene diisocyanate,trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylenediisocyanate, hexamethylene diisocyanate, propylene diisocyanate,ethylethylene diisocyanate, and trimethylhexane diisocyanate.

To prepare high-solids polyurethane solutions, use is made in particularof diisocyanates of the general formula (III′)

where X is a divalent aromatic hydrocarbon radical, preferably anunsubstituted or halogen-, methyl- or methoxy-substituted naphthylene,diphenylene or 1,2-, 1,3- or 1,4-phenylene radical, with particularpreference for a 1,3-phenylene radical and R₁ and R₂ are an alkylradical having 1-4 carbon atoms, preferably a methyl radical.Diisocyanates of the formula (III′) are known (their preparation isdescribed, for example, in EP-A-101 832, U.S. Pat. No. 3,290,350, U.S.Pat. No. 4,130,577, and U.S. Pat. No. 4,439,616) and some are availablecommercially (1,3-bis(2-isocyanatoprop-2-yl)benzene, for example, issold by the American Cyanamid company under the tradename TMXDI(META)®).

Further preferred as polyisocyanate components are diisocyanates of theformula (IV′):

where: R is a divalent alkyl or aralkyl radical having from 3 to 20carbon atoms and R′ is a divalent alkyl or aralkyl radical having from 1to 20 carbon atoms;

especially 1-isocyanato-2-(3-isocyanatoprop-1-yl)cyclohexane.

Polyurethanes are generally incompatible with water unless specificconstituents are incorporated and/or special preparation steps taken inthe course of their synthesis. To prepare the polyurethane resins it isthus possible to use compounds which contain two H-active groups thatare reactive with isocyanate groups, and at least one group whichensures dispersibility in water. Suitable groups of this kind arenonionic groups (e.g., polyethers), anionic groups, mixtures of thesetwo groups, or cationic groups.

Accordingly it is possible to build into the polyurethane resin an acidnumber which is sufficiently large that the neutralized product can bedispersed safely in water. For this purpose use is made of compoundscontaining at least one isocyanate-reactive group and at least one groupcapable of forming anions. Suitable isocyanate-reactive groups are, inparticular, hydroxyl groups and also primary and/or secondary aminogroups. Groups capable of forming anions are carboxyl, sulfonic acidand/or phosphonic acid groups. It is preferred to use alkanoic acidshaving two substituents on the alpha carbon atom. The substituent may bea hydroxyl group, an alkyl group or an alkylol group. These polyols haveat least one, generally from 1 to 3, carboxyl groups in the molecule.They have from 2 to about 25, preferably from 3 to 10 carbon atoms. Thecarboxyl-containing polyol may account for from 3 to 100% by weight,preferably from 5 to 50% by weight, of the overall polyol constituent inthe NCO prepolymer.

The amount of ionizable carboxyl groups that is available by virtue ofthe carboxyl group neutralization in salt form is generally at least0.4% by weight, preferably at least 0.7% by weight, based on the solids.The upper limit is approximately 12% by weight. The amount ofdihydroxyalkanoic acids in the unneutralized prepolymer gives an acidnumber of at least 5 mg KOH/g, preferably at least 10 mg KOH/g. Withvery low acid numbers, it is generally necessary to take furthermeasures to achieve dispersibility in water. The upper limit on the acidnumber is 150 mg KOH/g, preferably 40 mg KOH/g, based on the solids. Theacid number is preferably situated within the range from 20 to 40 mgKOH/g.

The isocyanate groups of the isocyanato-containing prepolymer arereacted with a modifier. The modifier is preferably added in an amountsuch that instances of chain extension and thus of molecular weightincrease occur. Modifiers used are preferably organic compoundscontaining hydroxyl and/or secondary and/or primary amino groups,especially polyols with a functionality of two, three and/or more.Examples of polyols which can be used include trimethylolpropane,1,3,4-butanetriol, glycerol, erythritol, mesoerythritol, arabitol,adonitol, etc. Trimethylolpropane is used with preference.

To prepare the polyurethane resin (A3) it is preferred first to preparean isocyanato-containing prepolymer from which the desired polyurethaneresin is then prepared by further reaction, preferably chain extension.The reaction of the components takes place in accordance with thewell-known processes of organic chemistry (cf., e.g.,Kunststoff-Handbuch, Volume 7: Polyurethane, edited by Dr. Y. Oertel,Carl Hanser Verlag, Munich, Vienna, 1983). Examples of the preparationof the prepolymers are described in DE-A 26 24 442 and DE-A 31 10 051.The polyurethane resins may be prepared by the known methods (e.g.,acetone method).

The components are preferably reacted in ethoxyethyl propionate (EEP) assolvent. The amount of EEP in this case may be variable within widelimits and should be sufficient for the formation of a prepolymersolution of appropriate viscosity. In general up to 70% by weight,preferably from 5 to 50% by weight, and with particular preference lessthan 20% by weight of solvent is used, based on the solids. Accordingly,the reaction may be carried out with very particular preference forexample, at a solvent content of 10-15% by weight EEP, based on thesolids.

The reaction of the components may take place if desired in the presenceof a catalyst, such as organotin compounds and/or tertiary amines.

To prepare the prepolymers, the amounts of the components are chosensuch that the equivalents ratio of NCO groups to OH groups is situatedbetween 2.0:1.0 and >1.0:1.0, preferably between 1.4:1 and 1.1:1.

The NCO prepolymer contains at least about 0.5% by weight of isocyanategroups, preferably at least 1% by weight of NCO, based on the solids.The upper limit is approximately 15% by weight, preferably 10% byweight, with particular preference 5% by weight of NCO.

Suitable components (A4) are all water-dilutable binders that arecompatible with the other constituents of component (I), examples ofsuch binders being acrylated polyurethane resins and/or polyesteracrylates.

Preferably, component (I) comprises as binder (A)

(A1) at least 20% by weight of at least one polyacrylate resin (A1),

(A2) from 0 to 30% by weight of at least one polyester (A2),

(A3) from 0 to 80% by weight of at least one polyurethane resin (A3),and

(A4) from 0 to 10% by weight of at least one further binder (A4),

the sum of the weight fractions of components (A1) to (A4) being in eachcase 100% by weight.

Besides constituents that are important to the invention, and thebinders (A), the component (I) may include as constituent (B) allcustomary coatings, pigments and/or fillers in fractions of from 0 to60% by weight, based on component (I). In this context it is possible touse not only the pigments that are common in aqueous compositions andwhich do not react with water and/or do not dissolve in water, and thepigments commonly employed in conventional coating compositions. Thepigments may comprise organic or inorganic compounds and may impartcolor and/or effect. The coating composition of the invention thereforeensures, owing to this large number of appropriate pigments, a universalscope for use, and permits the realization of a large number of shades.

As effect pigments it is possible to use metal flake pigments, such ascommercially customary aluminum bronzes, aluminum bronzes chromated inaccordance with DE-A-36 36 183, and commercially customary stainlesssteel bronzes, and also nonmetallic effect pigments, such as pearlescentpigments and interference pigments for example. Examples of suitableinorganic color pigments are titanium dioxides, iron oxides, Sicotransyellow, and carbon black. Examples of suitable organic color pigmentsare indanthrene blue, Cromophthal red, Irgazine organge and Heliogengreen. Examples of suitable fillers are chalk, calcium sulfates, bariumsulfate, silicates such as talc or kaolin, silicas, oxides such asaluminum hydroxide or magnesium hydroxide, nanoparticles or organicfillers such as textile fibers, cellulose fibers, polyethylene fibers orwood flour.

As a further constituent (C) the component (I) may include at least oneorganic solvent which may be diluted with water. Such solvents may alsoparticipate in the reaction with the crosslinking component (II) and maytherefore act as reactive diluents.

Examples of suitable solvents are the compounds already specified in thecontext of the preparation of the polyacrylate resins (A1) (see above).Also suitable are esters, ketones, keto esters, glycol ethers such asethylene, propylene or butylene glycol ethers, glycol esters such asethylene, propylene or butylene glycol esters, or glycol ether esterssuch as ethoxyethyl propionate and isopropoxypropanol. Further suitablesolvents include aliphatic and aromatic solvents such as dipentene,xylene or Shellsol®.

The solvents (C) may further consist in whole or in part of lowmolecular weight oligomeric compounds, which may be unreactive or elsereactive toward the crosslinking component (II). Where they arereactive, they comprise reactive diluents.

Examples of suitable reactive diluents are described above.

As constituent (D) the component (I) comprises, if desired, at least oneneutralizing agent.

Examples of suitable neutralizing agents for functional groups (i) whichcan be converted into cations are organic and inorganic acids such assulfuric acid, hydrochloric acid, phosphoric acid, formic acid, aceticacid, lactic acid, dimethylolpropionic acid or citric acid.

Examples of suitable neutralizing agents for functional groups (ii)which can be converted into anions are ammonia, ammonium salts, such asammonium carbonate or ammonium hydrogen carbonate, for example, and alsoamines, such as trimethylamine, triethylamine, tributylamine,dimethylaniline, diethylaniline, triphenylamine, dimethylethanolamine,diethylethanolamine, methyldiethanolamine, triethanolamine, and thelike. Neutralization may be effected in organic phase or in aqueousphase. Dimethylethanolamine is a preferred neutralizing agent used.

The amount of neutralizing agent (D) used in total in the coatingcomposition of the invention is chosen such that from 1 to 100equivalents, preferably from 50 to 90 equivalents, of the functionalgroups (i) or (ii) of the binder (A) are neutralized. The neutralizingagent (D) may be added to component (I), (II) and/or (III). Preferably,however, the neutralizing agent (D) is added to component (III).

As constituent (E) the component (I) may comprise at least one rheologycontrol additive. Examples of suitable rheology control additives arethose known from the patents WO 94/22968, EP-A-0 276 501, EP-A-0 249201, and WO 97/12945; crosslinked polymeric microparticles, as disclosedfor example in EP-A-0 008 127; inorganic phyllosilicates such asaluminum magnesium silicates, sodium magnesium phyllosilicates, andsodium magnesium fluorine lithium phyllosilicates of the montmorillonitetype; silicas; or synthetic polymers containing ionic and/or associativegroups, such as polyvinyl alcohol, poly(meth)acrylamide,poly(meth)acrylic acid, polyvinylpyrrolidone, styrene-maleic anhydrideor ethylene maleic anhydride copolymers and their derivatives, orhydrophobically modified ethoxylated urethanes or polyacrylates.Preferred rheology control additives used are polyurethanes.

The component (I) may further comprise at least one additional customarycoatings additive (E). Examples of such additives are defoamers,dispersing auxiliaries, emulsifiers, and leveling agents.

Of course, said additives (E) may also be added separately to thecoating composition. In this case the additives (E) are then referred toas component (IV).

To prepare the coating compositions of the invention it is preferred touse components (I) which consist of

from 20 to 90% by weight, preferably from 35 to 80% by weight, of thebinder (A), especially the polymeric or oligomeric resins (A1), (A2),(A3), and/or (A4),

from 0.1 to 80% by weight, preferably from 1 to 60% by weight, of theconstituent that is important to the invention,

from 0 to 60% by weight of at least one pigment and/or filler (B),

from 0 to 50% by weight, preferably from 10 to 40% by weight, of atleast one organic, optionally water-dilutable solvent (C),

from 0 to 20% by weight, preferably from 0.1 to 10% by weight, of atleast one neutralizing agent (D), and

from 0 to 20% by weight, preferably from 2 to 10% by weight, of at leastone customary auxiliary and/or additive (coatings additive) (E),

the sum of the weight fractions of components (A) to (E) being in eachcase 100% by weight.

The further key constituent of the coating composition of the inventionis at least one crosslinking agent (F) which is present in component(II).

The crosslinking agents (F) comprise at least one diisocyanate and/orpolyisocyanate (F) which if desired is dispersed or dissolved in one ormore organic, optionally water dilutable solvents.

The polyisocyanate component (F) comprises organic polyisocyanates,especially those known as paint polyisocyanates, containing freeisocyanate groups attached to aliphatic, cycloaliphatic, araliphaticand/or aromatic moieties. Preference is given to using polyisocyanatescontaining from 2 to 5 isocyanate groups per molecule and havingviscosities of from 100 to 10 000, preferably from 100 to 5 000, and,where manual mixing of the components (I), (II) and (III) isenvisaged—in particular from 1 000 to 2 000 mPas (at 23° C.). Ifdesired, small amounts of organic solvent may be added to thepolyisocyanates, preferably from 1 to 25% by weight based on straightpolyisocyanate, in order thus to improve the ease of incorporation ofthe isocyanate and, where appropriate, to lower the viscosity of thepolyisocyanate to a level within the aforementioned ranges. Examples ofsuitable solvent additives for the polyisocyanates are ethoxyethylpropionate, amyl methyl ketone, and butyl acetate. Furthermore, thepolyisocyanates may have been conventionally hydrophilically orhydrophobically modified.

Examples of suitable isocyanates are described by way of example in“Methoden der organischen Chemie”, Houben-Weyl, Volume 14/2, 4thEdition, Georg Thieme Verlag, Stuttgart 1963, pages 61 to 70, and by W.Siefken, Liebigs Annalen der Chemie, Volume 562, pages 75 to 136.Suitable examples include the isocyanates specified in the context ofthe description of the constituents that are important to the inventionor of the polyurethane resins (A3), and/or isocyanato-containingpolyurethane prepolymers which may be prepared by reacting polyols withan excess of polyisocyanates and which are preferably of low viscosity.

Further examples of suitable polyisocyanates are isocyanato-containingpolyurethane prepolymers which can be prepared by reacting polyols withan excess of polyisocyanates and are preferably of low viscosity. It isalso possible to use isocyanates containing isocyanurate, biuret,allophanate, iminooxadiazindione, urethane, urea and/or uretdionegroups. Polyisocyanates containing urethane groups, for example, areobtained by reacting some of the isocyanate groups with polyols, such astrimethylolpropane and glycerol, for example. It is preferred to usealiphatic or cycloaliphatic polyisocyanates, especially hexamethylenediisocyanate, dimerized and trimerized hexamethylene diisocyanate,isophorone diisocyante, 2-isocyanatopropylcyclohexyl isocyanate,dicyclohexylmethane 2,4′-diisocyanate, dicyclohexylmethane4,4′-diisocyanate or 1,3-bis-(isocyanatomethyl)cyclohexane,diisocyanates derived from dimer fatty acids, as sold under thecommercial designation DDI 1410 by Henkel,1,8-diisocyanato-4-isocyanatomethyloctane,1,7-diisocyanato-4-isocyanatomethylheptane or1-isocyanato-2-(3-isocyanatopropyl)-cyclohexane, or mixtures of thesepolyisocyanates.

Very particular preference is given to using mixtures of polyisocyanatescontaining uretdione and/or isocyanurate and/or allophanate groups andbased on hexamethylene diisocyanate, as formed by catalyticoligomerization of hexamethylene diisocyanate using appropriatecatalysts. The polyisocyanate constituent may further comprise anydesired mixtures of the free polyisocyanates exemplified.

The coating composition of the invention may further compriseisocyanato-free crosslinking agents (F′). Depending on their reactivity,these may be present in components (I), (II) and/or (III); the criticalfactor is that the crosslinking agents (F′) do not adversely affect thestorage stability of the component in question, such as by prematurecrosslinkinhg. The skilled worker will therefore be able to select theappropriate combinations of crosslinking agents (F′) on the one hand andcomponents (I), (II) and/or (III) on the other in a simple manner.

Examples of suitable crosslinking agents (F′) are blocked diisocyanatesand/or polyisocyanates based on the aforementioned diisocyanates and/orpolyisocyanates (F). Examples of suitable blocking agents are aliphatic,cycloaliphatic or araliphatic monoalcohols such as methyl, butyl, octylor lauryl alcohol, cyclohexanol or phenylcarbinol; hydroxylamines suchas ethanolamine; oximes such as methyl ethyl ketone oxime, acetone oximeor cyclohexanone oxime; amines such as dibutylamine or diisopropylamine;CH-acidic compounds such as malonic diesters or ethyl acetoacetate;heterocycles such as dimethylpyrazol; and/or lactams such asepsilon-caprolactam. These crosslinking agents (F′) may be present incomponents (I), (II) and/or (III).

Further examples of suitable crosslinking agents (F′) are polyepoxides(F′), especially all known aliphatic and/or cycloaliphatic and/oraromatic polyepoxides, based for example on bisphenol A or bisphenol F.Examples of suitable polyepoxides (F′) also include the polyepoxidesavailable commercially under the designations Epikote® from Shell,Denacol® from Nagase Chemicals Ltd., Japan, such as Denacol EX-411(pentaerythritol polyglycidyl ether), Denacol EX-321 (trimethylolpropanepolyglycidyl ether), Denacol EX-512 (polyglycerol polyglycidyl ether),and Denacol EX-521 (polyglycerol polyglycidyl ether). These crosslinkingagents (F′) may be present in components (I) and/or (III).

As crosslinking agents (F′) it is also possible to usetris(alkoxycarbonylamino)triazines of formula

These crosslinking agents (F′) may be present in components (I) and/or(III).

Examples of suitable tris (alkoxycarbonylamino) triazines (F′) aredescribed in the patents U.S. Pat. No. 4,939,213, U.S. Pat. No.5,084,541, and EP-A-0 624 577. The tris(methoxy-, tris(butoxy- and/ortris(2-ethylhexoxycarbonylamino)-triazines are used in particular.

The methyl butyl mixed esters, the butyl 2-ethylhexyl mixed esters, andthe butyl esters are of advantage. They have the advantage over thestraight methyl ester of better solubility in polymer melts, and alsohave less of a tendency to crystallize.

In particular it is possible to use amino resins, examples beingmelamine resins, as crosslinking agents (F′). In this context it ispossible to use any amino resins suitable for transparent topcoatmaterials or clearcoat materials, or a mixture of such amino resins.Particularly suitable are the customary and known amino resins some ofwhose methylol and/or methoxymethyl groups have been defunctionalized bymeans of carbamate or allophanate groups. Crosslinking agents of thistype are described in the patents U.S. Pat. No. 4,710,542 and EP-B-0 245700 and also in the article by B. Singh and coworkers,“Carbamylmethylated Melamines, Novel Crosslinkers for the CoatingsIndustry” in Advanced Organic Coatings Science and Technology Series,1991, Volume 13, pages 193 to 207. These crosslinking agents (F′) may bepresent in the components (I) and/or (III).

Further examples of suitable crosslinking agents (F′) arebeta-hydroxyalkylamides such asN,N,N′,N′-tetrakis-(2-hydroxyethyl)adipamide orN,N,N′,N′-tetrakis(2-hydroxypropyl)adipamide. These crosslinking agents(F′) may be present in components (I) and/or (III).

Further examples of suitable crosslinking agents (F′) are siloxanes,especially siloxanes containing at least one trialkoxy- ordialkoxysilane group. These crosslinking agents (F′) may be present incomponents (I), (II) and/or (III).

The polyisoscyanates (F) are used advantageously in an amount of atleast 70% by weight, with particular preference in an amount of 80 to100% by weight, based on the overall weight of the crosslinking agents(F) and (F′) in the coating composition of the invention.

The constituents (G) and (H) of component (II) correspond to theconstituents (C) and (E) of component (I), except that here constituentsare used which do not react to isocyanate groups.

To prepare the coating compositions of the invention it is preferred touse components (II) which consist of

(F) from 50 to 100% by weight, preferably from 60 to 90% by weight, ofat least one crosslinking agent,

(G) from 0 to 50% by weight, preferably from 10 to 40% by weight, of atleast one organic, optionally water dilutable solvent, and

(H) from 0 to 20% by weight, preferably from 0 to 10% by weight, of atleast one customary auxiliary and/or additive,

the sum of the weight fraction of components (F) to (H) being in eachcase 100% by weight.

The further key constituent of the coating composition of the inventionis component (III).

In accordance with the invention, this component (III) consists of orcomprises water. It is of advantage in accordance with the invention ifthe component (III) includes further suitable constituents in additionto water.

Examples of suitable constituents are the binders (A) described indetail above, especially the binders (A) containing

(i) functional groups which can be converted into cations byneutralizing agents and/or quaternizing agents, and/or cationic groups,or

(ii) functional groups which can be converted into anions byneutralizing agents, and/or anionic groups, and/or

(iii) nonionic hydrophilic groups.

Of these, the binders (A1), (A2) and/or (A3) and, where appropriate,(A4) dispersed or dissolved in water are particularly advantageous andtherefore used with particular preference.

Where component (I) includes binders (A) which are not, or not to anygreat extent, soluble or dispersible in water, it is advisable to use inparticular the binders (A1), (A2) and/or (A3) that are dispersed ordissolved in water.

Alternatively, the binders (A) may be in the form of a powder slurry. Inthis case the further flame retardants (F′) may be present in the powderslurry particles. Powder slurries are customary and known and aredescribed, for example, in the patents EP-A-0 652 264, U.S. Pat. No.4,268,542, DE-A-196 13 547, and DE-A-195 18 392.

The component (III) may further comprise at least one of theabove-described reactive diluents.

For preparing the coating compositions of the invention it is veryparticularly preferred to use components (III) which consist of

(J) from 40 to 90% by weight, preferably from 50 to 85% by weight, ofwater,

(K) from 5 to 50% by weight, preferably from 10 to 45% by weight, of thebinder (A), especially the polymeric or oligomeric resins (A1), (A2)and/or (A3) and, where appropriate (A4), in a form dissolved ordispersed in water,

(L) from 0 to 20% by weight, preferably 2 to 10% by weight, of at leastone neutralizing agent, and

(M) from 0 to 20% by weight, preferably from 2 to 10% by weight, of atleast one customary auxiliary and/or additive (coatings additive),

the sum of the weight fraction of components (J) to (M) being in eachcase 100% by weight.

The constituents (L) and (M) of component (III) correspond with theconstituents (D) and (E) of component (I).

The component (III) consisting of the water-dispersed form of component(A) and therefore of the water-dispersed form of the binders (A1), (A2)and/or (A3) and, where appropriate, (A4) may on the one hand be preparedby preparing the components in organic solvents, then neutralizing theacid groups, especially carboxyl groups, with the neutralizing agent (L)and, finally, introducing the neutralized constituents into deionizedwater, or on the other hand may be prepared by emulsion polymerizationof the monomeric building blocks of the binders (A) in water.

Preferably, the components (A1), (A2) and/or (A3) and, whereappropriate, (A4) are first prepared in organic solvents, thenneutralized and, finally, dispersed in water in neutralized form.

In the course of the preparation of the water-dispersed form of thepolyacrylate resins (A1), the polymerization in the organic solvent ispreferably conducted in a plurality of stages with separate monomer andinitiator feeds. With very particular preference, the polyacrylate resin(A1) is prepared by the two-stage process already described above, by

1. polymerizing a mixture of (a1), (a2), (a4), (a5), and (a6), or amixture of portions of components (a1), (a2), (a4), (a5), and (a6), inan organic solvent,

2. after at least 60% by weight of the mixture consisting of (a1), (a2),(a4), (a5), and, where used, (a6) have been added, adding (a3) and anyremainder of components (a1), (a2), (a4), (a5), and (a6), and continuingpolymerization, and

3. after the end of the polymerization, subjecting the resultingpolyacrylate resin (A1) if desired to at least partial neutralization.

Examples of suitable neutralizing agents (L) as used in step 3. are theammonia, ammonium salts and amines (constituent (D) of component (I))already described in connection with the preparation of component (I),it being possible for the neutralization to take place in organic phaseor in aqueous phase. The total amount of neutralizing agent (L) used toneutralize the component (A1) is chosen so that from 1 to 100equivalents, preferably from 50 to 90 equivalents, of the acid groups ofthe binder (A1) are neutralized.

Used as preference as constituents (A2) in component (III) arepolyesters (A2) prepared by a two-stage process comprising firstpreparing a hydroxyl-containing polyester having an OH number from 100to 300 mg KOH/g, an acid number of less than 10 mg KOH/g, and a numberaverage molecular weight Mn of from 500 to 2 000 daltons, which is thenreacted in a second stage with carboxylic anhydrides to give the desiredpolyester (A2). The amount of carboxylic anhydrides is chosen such thatthe resulting polyester has the desired acid number.

After the end of the reaction the polyester (A2) is subjected to atleast partial neutralization, in which case it is again possible to usethe neutralizing agent (L) (constituent (D) of component (I)) alreadydescribed in connection with the preparation of component (I) and forthe neutralization to take place in organic phase or in aqueous phase.

To prepare the polyurethane resins (A3) for component (III) it ispreferred first to prepare an isocyanato-containing prepolymer fromwhich the polyurethane resin (A3) is then prepared by further reaction,preferably by chain extension.

After the end of the polymerization the resulting polyurethane resin issubjected to at least partial neutralization, in which case it is againpossible to use the neutralizing agent (L) (constituent (D) of component(I)) already described in connection with the preparation of component(I) and for the neutralization to take place in organic phase or inaqueous phase.

Suitable components (A4) which are additionally present whereappropriate are all water dilutable and/or water dispersible bindersthat are compatible with the other constituents of component (III),examples of such binders including acrylated polyurethane resins and/orpolyester acrylates.

To prepare the coating compositions, components (I), (II) and (III) areused preferably in amounts such that the equivalents ratio of hydroxylgroups of the constituents that are important to the invention, of thebinders (A) and of the reactive diluents, where present, to thecrosslinking groups of the crosslinking agent (F) and also, whereappropreiate, (F′) is situated between 1:2 and 2:1, preferably between1:1.2 and 1:1.5.

Furthermore, the coating compositions of the invention preferablycomprise in total

from 1 to 60% by weight, preferably from 1 to 40% by weight, ofconstituents that are important to the invention,

from 15 to 60% by weight, preferably from 20 to 50% by weight, ofbinders (A),

from 5 to 30% by weight, preferably from 10 to 20% by weight, ofcrosslinking agents (F),

from 5 to 25% by weight, preferably from 10 to 20% by weight, of organicsolvents (C),

from 25 to 60% by weight, preferably from 30 to 50% by weight, of water,

from 0 to 50% by weight, preferably from 0 to 30% by weight, of pigmentsand/or fillers (B), and

from 0 to 10% by weight of customary coating additives (E),

based in each case on the overall weight of the coating composition ofthe invention.

The preparation of component (I) takes place in accordance with methodsknown to the skilled worker by mixing and, where appropriate, dispersingof the individual constituents. For example, color pigments (B) arenormally incorporated by grinding (dispersing) the respective pigmentsin one or more binders. The dispersing of the pigments takes place withthe aid of customary apparatus, such as bead mills and sand mills, forexample.

Components (II), (III) and, where appropriate, (IV) are likewiseprepared in accordance with methods well known to the skilled worker, bymixing and/or dispersing the individual constituents.

The coating compositions of the invention are prepared in particular bythe following mixing method from components (I), (II), (III) and, whereappropriate, (IV):

To prepare the coating compositions of the invention, first of allcomponents (I) and (II) are mixed, these components (I) and (II)preferably containing no neutralizing agent. Then component (IV), whereappropriate, is added to this mixture. Then either the resulting mixtureis added to component (III) comprising neutralizing agent (L) and theresulting coating composition is dispersed, or component (III)comprising neutralizing agent (L) is added to the resulting mixture.

Furthermore, the coating composition of the invention may be prepared inanalogy to the process just described, in which case, however, theneutralizing agent (L) is not present in component (III) but is insteadadded separately prior to the addition of component (III).

Furthermore, the coating composition of the invention may also beprepared by first adding the neutralizing agent (L) to component (I).Instead of this mixing it is of course also possible to use a component(I) which already contains the neutralizing agent (L). The resultingcomponent (I) is then mixed with component (II) and, where appropriate,with component (IV) (simultaneous or successive mixing with (II) and,where appropriate (IV)), then either the resulting mixture is added tocomponent (III) or component (III) is added to it, and the coatingcomposition thus obtained in each case is homogenized by dispersing.

If binders (A) containing exclusively nonionic hydrophilic groups (iii)are used, the use of the neutralizing agent (L) is omitted.

The coating compositions of the invention may be applied to any desiredsubstrates, such as metal, wood, plastic, glass or paper, for example,by customary application methods, such as spraying, knife coating,brushing, dipping, rolling or flow coating, for example.

Because of their composition, the coating compositions of the inventionare curable both thermally and by means of radiation. Thermal curing andradiation curing may take place simultaneously. In accordance with theinvention it is of advantage to carry out the two curing steps insuccession, and so this method is employed with preference.

Thermal curing takes place at temperatures below 150° C., preferably attemperatures of not more than 140° C. In specific embodiments of thecoating compositions of the invention, however, it is also possible toemploy higher curing temperatures.

The curing of the coating compositions of the invention by radiation,especially UV radiation, has no special features in terms of itsmethodology but is instead carried out in customary and known unitsunder the conditions described for example, by R. Holmes in U.V. andE.B. Curing Formulations for Printing Inks, Coatings and Paints, SITATechnology, Academic Press, London, United Kingdom 1984, or by D. Stoyeand W. Freitag (editors) in Paints, Coatings and Solvents, Second,Completely Revised Edition, Wiley-VCH, Weinheim, N.Y., 1998.

The coating compositions of the invention are preferably used to producetopcoats. The coating compositions of the invention may be used both inthe OEM finishing and in the refinish of automobile bodies. However,they are preferably used in the area of the refinish and finishing ofplastics parts.

The aqueous coating compositions of the invention may be used aspower-surfacers and also to produce single-coat topcoats, and also aspigmented basecoat materials or as clearcoat materials in a process forproducing a multicoat system (basecoat-clearcoat process).

EXAMPLES Preparation Example 1 The Preparation of a Polyacrylate Resin(A1-1)

25 kg of ethoxyethyl propionate (EEP) were weighed into a 100 kilogramsteel reactor suitable for polymerization and equipped with monomerfeed, initiator feed, temperature measurement means, oil heating andreflux condenser, and were heated to 130° C. A mixture of 7.13 kg ofbutyl methacrylate, 5.72 kg of methyl methacrylate, 5.96 kg of styrene,3.16 kg of lauryl methacrylate and 6.76 kg of hydroxyethyl acrylate wasmetered in at a uniform rate with stirring over the course of fourhours. The initiator feed was started five minutes before this feed. Theinitiator solution (2.74 kg of tert-butyl peroxyethylhexanoate in 4.48kg of EEP) was metered in at a uniform rate over 4.5 hours. After 2.5hours of the metering time of the first monomer feed, the second monomerfeed was started. It consisted of 2.8 kg of hydroxyethyl acrylate, 1.36kg of acrylic acid and 0.68 kg of EEP and was metered in at a uniformrate over 1.5 hours.

This gave the polyacrylate resin (A1-1) having a solids content of 79.2%(one hour; 130° C.), an acid number of 31.1 mg KOH/g and a viscosity of4.4 dPas (55% in EEP).

Preparation Example 2 The Preparation of a Polyester Resin Precursor

A 4 liter steel reactor suitable for polycondensation reactions wascharged with 1 088 g of neopentyl glycol hydroxypivalate, 120 g ofphthalic anhydride, 1 268 g of isophthalic acid, 21 g ofbutylethylpropanediol, 489 g of neopentyl glycol and 113 g of xylene.This initial charge was then heated and the water of condensation wasremoved continuously until an acid number of 3.5 mg KOH/g was reached.Thereafter a solids content of 79.7% was set using EEP. The acid numberof the resulting polyester resin (A2) was 4.4 mg KOH/g, its viscosity3.6 dPas (60% in EEP).

Preparation Example 3 The Preparation of a Water-dispersed PolyurethaneResin (A3) for use in Accordance With the Invention

A 4 liter steel reactor suitable for polyurethane resin synthesis wascharged with 749 g of the polyester resin precursor from PreparationExample 2, 6.6 g of ethylbutylpropanediol, 69 g of dimethylolpropionicacid and 318 g of m-tetramethylxylylene diisocyanate and this initialcharge was left to react at a product temperature of 110° C. until aconstant isocyanate content was reached. Then 101 g oftrimethylolpropane were added in one portion and heating was continueduntil the reaction was ended. Subsequently 31.5 g of EEP were added.After stirring for 30 minutes, the product was neutralized with 36.7 gof dimethylethanolamine. The resultant polyurethane resin (A3) wasdispersed at from 90 to 110° C. in 1 929.2 g of water whose temperaturewas 60° C. The resultant dispersion was free from gel particles, washomogeneous, and had a solids content of 36.1%, an acid number of 30.3mg KOH/g, and a pH of 7.1. The dispersions were stable on storage at 40°C. for longer than four weeks.

Preparation Example 4 The Preparation of a Water-dispersed PolyacrylateResin (A1-2) for use in Accordance With the Invention

The polyacrylate resin was prepared in a 4 liter steel rector withstirrer, reflux condenser, 2 monomer feeds and one initiator feed. 385 gof n-butanol were introduced as initial charge and heated to 110° C.Over the course of five hours, a mixture of 255 g of butyl methacrylate,197 g of methyl methacrylate, 181 g of styrene, 113 g of Methacrylester13 (methacrylic alkyl ester from Rohm & Haas) and 215 g of hydroxyethylacrylate was metered in. After 3.5 hours of the first monomer feed, asecond monomer feed comprising 113 g of hydroxyethyl methacrylate and 58g of acrylic acid was started and was metered in at a uniform rate overthe course of 1.5 hours. Subsequently, polymerization was continued fortwo hours. Following neutralization with 63 g of dimethylethanolamine,the product was stirred for a further 30 minutes. The resultantneutralized polyacrylate resin (A1-2) was dispersed in 1 338 g ofdeinoized water. The organic solvent was distilled off in vacuo to aresidual content <1.5%. After the solids content had been adjusted to39.9% using deionized water, the resultant dispersion was characterized.Its pH was 7.2, its acid number 41.4 mg KOH/g. It exhibitedpseudoplasticity and was stable on storage at 40° C. for more than fourweeks.

Example 1 Preparation of an Inventive Coating Composition 1.1 ThePreparation of Component (I)

Component (I) was prepared by mixing the following constituents with oneanother using a stirrer (600 rpm):

70.44 parts by weight of the polyacrylate resin (A1-1) from PreparationExample 1,

40.00 parts by weight of urethane acrylate Laromer® 8987 from BASFAktiengesellschaft,

4.24 parts by weight of dibasic ester (DBE: mixture of dimethyl adipate,glutarate and succinate from DuPont),

12.76 parts by weight of butyl glycol acetate,

4.24 parts by weight of a commercial wetting agent (Tensid S fromBiesterfeld),

0.88 part by weight of a leveling agent based on a polyether-modifieddimethylsiloxane copolymer (Byk® 333 from Byk Gulden),

0.88 part by weight of a commercial silicone additive (Tego Glide® 410from Tego Chemie),

2.52 parts by weight of a fluorine-containing leveling agent (Fluorad®FL 430, 10% in butyl glycol acetate, from 3 M),

1.76 parts by weight of a commercial light stabilizer (Tinuvin® 292 fromCiba),

1.28 parts by weight of a further commercial light stabilizer (Tinuvin®1130 from Ciba), and

1.40 parts by weight of a commercial photoinitiator (Irgacure® 184 fromCiba Geigy).

1.2 The Preparation of Component (II)

Component (II) was prepared by mixing 44.6 parts by weight of Desmodur®2025/1 (polyisocyanate of the hexamethylene diisocyanate type having anisocyanate content of 23%, from Bayer) and 6.44 parts by weight of butylglycol acetate with one another.

1.3 The Preparation of Component (III)

Component (III) was prepared by mixing 72.48 parts by weight ofdeionized water, 1.76 parts by weight of dimethylethanolamine, 44.8parts by weight of a polyacrylate resin dispersion (A3) from PreparationExample 4, and 89.52 parts by weight of a polyurethane resin dispersion(A1-2) from Preparation Example 3 with one another.

1.4 The Preparation of an Inventive Clearcoat Material

The inventive clearcoat material was prepared by mixing theabove-described components (I), (II) and (III) with one another and withstirring. The resultant clearcoat material had a viscosity of 35 s (DIN4 cup); therefore, it was directly suitable for application.

1.5 The Production of Inventive Coatings and Test panels

Steel panels which had been coated conventionally with anelectrodeposition coating material and a primer-surfacer were coatedwith a black basecoat material in a thickness of from 12 to 15 μm. Thebasecoat was dried at 80° C. for ten minutes. Subsequently the inventiveclearcoat material was applied at different film thicknesses.

In the case of Example 1.5a, the steel panels were dried at roomtemperature for 15 minutes and at 80° C. for 10 minutes and then bakedat 140° C. This was followed by UV curing at about 2 000 mJ/cm².

In the case of Example 1.5b, the steel panels were dried at roomtemperature for 15 minutes. This was followed by UV curing at about 2000 mJ/cm². They were subsequently dried at 80° C. for 10 minutes andthen baked at 140° C.

In both cases the popping limit was 58 μm; only a few fine pinholesoccurred.

The gloss at 20° in accordance with DIN 67530 was found to be 84.1 inthe case of Example 1.5a and 84.5 in the case of Example 1.5b.

The gray haze was measured using the Microgloss Haze hazemeter fromByk-Gardner; in both examples the figure was below 20.

In the case of both examples, runs occurred only above a film thicknessof 55 μm.

What is claimed is:
 1. A coating composition comprising at least threecomponents, comprising (I) a component comprising at least oneoligomeric or polymeric resin containing functional groups which reactwith isocyanate groups, as binder (A), (II) a component comprising atleast one polyisocyanate as crosslinking agent (F), and (III) acomponent which comprises water, wherein component (I), (II) and/or(III) comprise or comprises at least one constituent which is curable bymeans selected from actinic light, electron beams and mixtures thereof.2. The coating composition as claimed in claim 1, comprising theconstituent curable with actinic light and/or electron beams in anamount, based on the overall amount of the coating composition, of from0.1 to 80% by weight.
 3. The coating composition as claimed in claim 1,wherein the constituent curable with actinic light and/or electron beamscomprises at least one radiation curable binder, based on compoundsselected from the group consisting of ethylenically unsaturatedprepolymers, ethylenically unsaturated oligomers and mixtures thereof.4. The coating composition as claimed in claim 3, wherein theconstituent curable with actinic light and/or electron beams comprisesone or more reactive diluents.
 5. The coating composition as claimed inclaim 4, comprising binders selected from the group consisting of(meth)acryloyl- functional (meth)acrylic copolymers, polyetheracrylates, polyester acrylates, unsaturated polyesters, epoxy acrylates,urethane acrylates, amino acrylates, melamine acrylates, siliconeacrylates, and the corresponding methacrylates and mixtures thereof. 6.The coating composition as claimed in claim 5, wherein the binders arefree from aromatic structural units.
 7. The coating composition asclaimed in claim 5 wherein the binder is selected from the groupconsisting of urethane (meth)acrylates, poly- ester (meth)acrylates, andmixtures thereof.
 8. The coating composition as claimed in claim 3,wherein the polymers and/or oligomers used as binders have a numberaverage molecular weight of from 500 to 50
 000. 9. The coatingcomposition as claimed in claim 3, wherein binders employed comprisepolymers and/or oligomers containing per molecule at least 2 doublebonds and having a double bond equivalent weight of from 400 to 2 000,and a viscosity at 23° C. of from 250 to 11 000 mPa.s.
 10. The coatingcomposition as claimed in claim 1, wherein the functional groups whichreact with isocyanate groups comprise hydroxyl groups.
 11. The coatingcomposition as claimed in claim 1, wherein component (III) comprises atleast one binder (A).
 12. The coating composition as claimed in claim 1,wherein component (I) comprises at least one water soluble ordispersible binder (A) and/or component (III) comprises at least onebinder (A) dispersed or dissolved in water.
 13. The coating compositionas claimed in claim 12, wherein the binders (A) comprise functionalgroups selected from the group consisting of (i) functional groups whichare converted into cations by neutralizing agents and compounds selectedfrom the group consisting of quaternizing agents, and cationic groups,and mixtures thereof, (ii) functional groups which can be converted intoanions by neutralizing agents, and compounds selected from the groupconsisting of anionic groups, and mixtures thereof, and (iii) nonionichydrophilic groups.
 14. The coating composition as claimed in claim 13,wherein the binders (A) contain groups selected from the groupconsisting of carboxylic acid and carboxylate groups (ii) and mixturesthereof.
 15. The coating composition as claimed in claim 14, whereinsome of the binders (A) in component (III) are in powder slurryparticles.
 16. (Previously Amended) The coating composition as claimedin claim 14, wherein component (I) comprises as binders (A), bindersselected from the group consisting of (A1) at least one acrylatecopolymer (A1) which is dispersible or soluble in one or more organicsolvents, contains groups selected from the group consisting of hydroxylgroups and carboxylic acid groups, carboxylate groups, and mixturesthereof, and has a number average molecular weight Mn of between 1000and 30000 daltons, an OH number of from 40 to 200 mg KOH/g, and an acidnumber of from 5 to 150 mg KOH/g, (A2) at least one polyester resin (A2)which is dispersible or soluble in one or more organic solvents,contains groups selected from the group consisting of hydroxyl,carboxylic acid and carboxylate groups, and mixtures thereof and has anumber average molecular weight Mn of between 1000 and 30 000 daltons,an OH number of from 30 to 250 mg KOH/g, and an acid number of from 5 to150 mg KOH/g, and (A3) at least one polyurethane resin (A3) which isdispersible or soluble in one or more organic solvents, contains groupsselected from the group consisting of hydroxyl, carboxylic acid andcarboxylate groups, and mixtures thereof and has a number averagemolecular weight Mn of between 1 000 and 30 000 daltons, an OH number offrom 20 to 200 mg KOH/g, and an acid number of from 5 to 150 mg KOH/g.17. The coating composition as claimed in claim 1, further comprising,crosslinking agent (F′) comprising at least one compound selected fromthe group consisting epoxide compounds containing at least two epoxidegroups per molecule, amino resins, blocked polyisocyanates, tris(alkoxy-carbonylamino)triazines, siloxanes and beta-hydroxyalkylamides andmixtures thereof.
 18. The coating composition as claimed in claim 1,wherein component (I) further comprises at least one functionalizedalkane that is present in an amount of from 1 to 80% by weight, based onthe overall amount of binder (A) and the at least one functionalizedalkanes.
 19. The coating composition as claimed in claim 3, wherein theconstituent curable with actinic light and/or electron beams comprisesone or more photoinitiators.
 20. The coating composition as claimed inclaim 5, wherein the binder is selected from the group consisting ofaliphatic urethane acrylates and mixtures thereof.
 21. The coatingcomposition as claimed in claim 3, wherein binders employed comprisepolymers and/or oligomers containing per molecule from 3 to 6, doublebonds and having a double bond equivalent weight of from 500 to 900, anda viscosity at 23° C. of from 250 to 11 000 mPa.s.
 22. The coatingcomposition as claimed in claim 14, wherein all binders (A) in component(III) are in powder slurry particles.
 23. The coating composition asclaimed in claim 14, wherein component (I) comprises as binder (A) (A1)at least one acrylate copolymer (A1) which is dispersible or soluble inone or more organic, water dilutable solvents, contains groups selectedfrom the group consisting of hydroxyl, carbokylic acid, and carboxylategroups and mixtures thereof, and has a number average molecular weightMn of between 1000 and 30000 daltons, an OH number of from 40 to 200 mgKOH/g, and an acid number of from 5 to 150 mg KOH/g.
 24. The coatingcomposition as claimed in claim 14, wherein component (III) comprises asbinder (A) (A1) at least one acrylate copolymer (A1) which isdispersible or soluble in one or more organic solvents, and whichcontains groups selected from the group consisting of hydroxyl,carboxylic acid and carboxylate groups, and mixures thereof and has anumber average molecular weight Mn of between 1000 and 30,000 daltons,an OH number of from 40 to 200 mg KOH/g, and an acid number of from 5 to150 mg KOH/g.
 25. The coating composition as claimed in claim 16,wherein component ((III) comprises as binders (A) (A1) at least oneacrylate copolymer (A1) which is dispersible or soluble in one or moreorganic solvents, contains groups selected from hydroxyl, carboxylicacid and carboxylate groups and mixtures thereof, and has a numberaverage molecular weight Mn of between 1000 and 30000 daltons, an OHnumber of from 40 to 200 mg KOH/g, and an acid number of from 5 to 150mg KOH/g.
 26. The coating composition as claimed in claim 1, whereincomponent (I) further comprises at least one functionalized alkane thatis present in an amount of from 5 to 50% by weight, based on the overallamount of binder (A) and the at least one functionalized alkanes. 27.The coating composition as claimed in claim 1, wherein component (1)further comprises at least one functionalized alkane that is present inan amount of from 10 to 35% by weight, based on the overall amount ofbinder (A) and the at least one functionalized alkanes.
 28. The coatingcomposition as claimed in claim 1, wherein component (III) furthercomprises at least one functionalized alkane That is present in anamount of from 1 to 80% by weight, based on the overall amount of binder(A) and the at least one functionalized alkanes.
 29. The coatingcomposition as claimed in claim 1, wherein component (III) furthercomprises at least one functionalized alkane that is present in anamount of from 5 to 50% by weight, based on the overall amount of binder(A) and the at least one functionalized alkanes.
 30. The coatingcomposition as claimed in claim 1, wherein component (III) furthercomprises at least one functionalized alkane That is present in anamount from 10 to 35% by weight, based on the overall amount of binder(A) and the at least one functionalized alkanes.
 31. The coatingcomposition as claimed in claim 1, wherein components (I) and (III) eachfurther comprise at least one functionalized alkane that are present inan amount of from 1 to 80% by weight, based on the overall amount ofbinder (A) and the at least one functionalized alkanes.
 32. The coatingcomposition as claimed in claim 1, wherein components (I) and (III) eachfurther comprise at least one functionalized alkane that are present inan amount of from 5 to 50% by weight, based on the overall amount ofbinder (A) and the at least one functionalized alkanes.
 33. The coatingcomposition as claimed in claim 1, wherein components (I) and (III) eachfurther comprise at least one functionalized alkane that are present inan amount of from 10 to 35% by weight, based on the overall amount ofbinder (A) and the at least one functionalized alkanes.
 34. A coatingcomposition selected from the group consisting of refinish coatings,automotive OEM coatings, plastics coatings and topcoat coatings andprimer-surfacer coatings, comprising the coating of claim
 1. 35. Thecoating composition of claim 1 further comprising at least one of aC₉-C₁₆ cyclic alkane functionalized with two hydroxyl groups and aC₉-C₁₆ acyclic alkane functionalized with at least two hydroxyl groups.36. The coating composition of claim 1, wherein the binder contains atleast two double bonds per molecule.